@article {923, title = {Alternative genomic diagnoses for individuals with a clinical diagnosis of Dubowitz syndrome.}, journal = {Am J Med Genet A}, volume = {185}, year = {2021}, month = {2021 01}, pages = {119-133}, abstract = {

Dubowitz syndrome (DubS) is considered a recognizable syndrome characterized by a distinctive facial appearance and deficits in growth and development. There have been over 200 individuals reported with Dubowitz or a "Dubowitz-like" condition, although no single gene has been implicated as responsible for its cause. We have performed exome (ES) or genome sequencing (GS) for 31 individuals clinically diagnosed with DubS. After genome-wide sequencing, rare variant filtering and computational and Mendelian genomic analyses, a presumptive molecular diagnosis was made in 13/27 (48\%) families. The molecular diagnoses included biallelic variants in SKIV2L, SLC35C1, BRCA1, NSUN2; de novo variants in ARID1B, ARID1A, CREBBP, POGZ, TAF1, HDAC8, and copy-number variation at1p36.11(ARID1A), 8q22.2(VPS13B), Xp22, and Xq13(HDAC8). Variants of unknown significance in known disease genes, and also in genes of uncertain significance, were observed in 7/27 (26\%) additional families. Only one gene, HDAC8, could explain the phenotype in more than one family (N = 2). All but two of the genomic diagnoses were for genes discovered, or for conditions recognized, since the introduction of next-generation sequencing. Overall, the DubS-like clinical phenotype is associated with extensive locus heterogeneity and the molecular diagnoses made are for emerging clinical conditions sharing characteristic features that overlap the DubS phenotype.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.61926}, author = {Dyment, David A and O{\textquoteright}Donnell-Luria, Anne and Agrawal, Pankaj B and Coban Akdemir, Zeynep and Aleck, Kyrieckos A and Antaki, Danny and Al Sharhan, Hind and Au, Ping-Yee B and Aydin, Hatip and Beggs, Alan H and Bilguvar, Kaya and Boerwinkle, Eric and Brand, Harrison and Brownstein, Catherine A and Buyske, Steve and Chodirker, Bernard and Choi, Jungmin and Chudley, Albert E and Clericuzio, Carol L and Cox, Gerald F and Curry, Cynthia and de Boer, Elke and de Vries, Bert B A and Dunn, Kathryn and Dutmer, Cullen M and England, Eleina M and Fahrner, Jill A and Geckinli, Bilgen B and Genetti, Casie A and Gezdirici, Alper and Gibson, William T and Gleeson, Joseph G and Greenberg, Cheryl R and Hall, April and Hamosh, Ada and Hartley, Taila and Jhangiani, Shalini N and Karaca, Ender and Kernohan, Kristin and Lauzon, Julie L and Lewis, M E Suzanne and Lowry, R Brian and L{\'o}pez-Gir{\'a}ldez, Francesc and Matise, Tara C and McEvoy-Venneri, Jennifer and McInnes, Brenda and Mhanni, Aziz and Garcia Minaur, Sixto and Moilanen, Jukka and Nguyen, An and Nowaczyk, Malgorzata J M and Posey, Jennifer E and {\~O}unap, Katrin and Pehlivan, Davut and Pajusalu, Sander and Penney, Lynette S and Poterba, Timothy and Prontera, Paolo and Doriqui, Maria Juliana Rodovalho and Sawyer, Sarah L and Sobreira, Nara and Stanley, Valentina and Torun, Deniz and Wargowski, David and Witmer, P Dane and Wong, Isaac and Xing, Jinchuan and Zaki, MAH S and Zhang, Yeting and Boycott, Kym M and Bamshad, Michael J and Nickerson, Deborah A and Blue, Elizabeth E and Innes, A Micheil} } @article {916, title = {Biallelic variants in HPDL, encoding 4-hydroxyphenylpyruvate dioxygenase-like protein, lead to an infantile neurodegenerative condition.}, journal = {Genet Med}, volume = {23}, year = {2021}, month = {2021 03}, pages = {524-533}, abstract = {

PURPOSE: Dioxygenases are oxidoreductase enzymes with roles in metabolic pathways necessary for aerobic life. 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL), encoded by HPDL, is an orphan paralogue of 4-hydroxyphenylpyruvate dioxygenase (HPD), an iron-dependent dioxygenase involved in tyrosine catabolism. The function and association of HPDL with human diseases remain unknown.

METHODS: We applied exome sequencing in a cohort of over 10,000 individuals with neurodevelopmental diseases. Effects of HPDL loss were investigated in vitro and in vivo, and through mass spectrometry analysis. Evolutionary analysis was performed to investigate the potential functional separation of HPDL from HPD.

RESULTS: We identified biallelic variants in HPDL in eight families displaying recessive inheritance. Knockout mice closely phenocopied humans and showed evidence of apoptosis in multiple cellular lineages within the cerebral cortex. HPDL is a single-exonic gene that likely arose from a retrotransposition event at the base of the tetrapod lineage, and unlike HPD, HPDL is mitochondria-localized. Metabolic profiling of HPDL mutant cells and mice showed no evidence of altered tyrosine metabolites, but rather notable accumulations in other metabolic pathways.

CONCLUSION: The mitochondrial localization, along with its disrupted metabolic profile, suggests HPDL loss in humans links to a unique neurometabolic mitochondrial infantile neurodegenerative condition.

}, keywords = {4-Hydroxyphenylpyruvate Dioxygenase, Animals, Dioxygenases, Exons, Mice, Mice, Knockout, Phenotype}, issn = {1530-0366}, doi = {10.1038/s41436-020-01010-y}, author = {Ghosh, Shereen G and Lee, Sangmoon and Fabunan, Rudy and Chai, Guoliang and Zaki, MAH S and Abdel-Salam, Ghada and Sultan, Tipu and Ben-Omran, Tawfeg and Alvi, Javeria Raza and McEvoy-Venneri, Jennifer and Stanley, Valentina and Patel, Aakash and Ross, Danica and Ding, Jeffrey and Jain, Mohit and Pan, Daqiang and L{\"u}bbert, Philipp and Kammerer, Bernd and Wiedemann, Nils and Verhoeven-Duif, Nanda M and Jans, Judith J and Murphy, David and Toosi, Mehran Beiraghi and Ashrafzadeh, Farah and Imannezhad, Shima and Karimiani, Ehsan Ghayoor and Ibrahim, Khalid and Waters, Elizabeth R and Maroofian, Reza and Gleeson, Joseph G} } @article {1001, title = {Loss of function mutations in GEMIN5 cause a neurodevelopmental disorder.}, journal = {Nat Commun}, volume = {12}, year = {2021}, month = {2021 05 07}, pages = {2558}, abstract = {

GEMIN5, an RNA-binding protein is essential for assembly of the survival motor neuron (SMN) protein complex and facilitates the formation of small nuclear ribonucleoproteins (snRNPs), the building blocks of spliceosomes. Here, we have identified 30 affected individuals from 22 unrelated families presenting with developmental delay, hypotonia, and cerebellar ataxia harboring biallelic variants in the GEMIN5 gene. Mutations in GEMIN5 perturb the subcellular distribution, stability, and expression of GEMIN5 protein and its interacting partners in patient iPSC-derived neurons, suggesting a potential loss-of-function mechanism. GEMIN5 mutations result in disruption of snRNP complex assembly formation in patient iPSC neurons. Furthermore, knock down of rigor mortis, the fly homolog of human GEMIN5, leads to developmental defects, motor dysfunction, and a reduced lifespan. Interestingly, we observed that GEMIN5 variants disrupt a distinct set of transcripts and pathways as compared to SMA patient neurons, suggesting different molecular pathomechanisms. These findings collectively provide evidence that pathogenic variants in GEMIN5 perturb physiological functions and result in a neurodevelopmental delay and ataxia syndrome.

}, keywords = {Alleles, Amino Acid Sequence, Animals, Child, Preschool, Developmental Disabilities, Drosophila, Female, Gene Expression Regulation, Developmental, Gene Knockdown Techniques, Gene Ontology, HEK293 Cells, Humans, Induced Pluripotent Stem Cells, Loss of Function Mutation, Male, Muscle Hypotonia, Myoclonic Cerebellar Dyssynergia, Neurodevelopmental Disorders, Neurons, Pedigree, Polymorphism, Single Nucleotide, Ribonucleoproteins, Small Nuclear, Rigor Mortis, RNA-Seq, SMN Complex Proteins}, issn = {2041-1723}, doi = {10.1038/s41467-021-22627-w}, author = {Kour, Sukhleen and Rajan, Deepa S and Fortuna, Tyler R and Anderson, Eric N and Ward, Caroline and Lee, Youngha and Lee, Sangmoon and Shin, Yong Beom and Chae, Jong-Hee and Choi, Murim and Siquier, Karine and Cantagrel, Vincent and Amiel, Jeanne and Stolerman, Elliot S and Barnett, Sarah S and Cousin, Margot A and Castro, Diana and McDonald, Kimberly and Kirmse, Brian and Nemeth, Andrea H and Rajasundaram, Dhivyaa and Innes, A Micheil and Lynch, Danielle and Frosk, Patrick and Collins, Abigail and Gibbons, Melissa and Yang, Michele and Desguerre, Isabelle and Boddaert, Nathalie and Gitiaux, Cyril and Rydning, Siri Lynne and Selmer, Kaja K and Urreizti, Roser and Garcia-Oguiza, Alberto and Osorio, Andr{\'e}s Nascimento and Verdura, Edgard and Pujol, Aurora and McCurry, Hannah R and Landers, John E and Agnihotri, Sameer and Andriescu, E Corina and Moody, Shade B and Phornphutkul, Chanika and Sacoto, Maria J Guillen and Begtrup, Amber and Houlden, Henry and Kirschner, Janbernd and Schorling, David and Rudnik-Sch{\"o}neborn, Sabine and Strom, Tim M and Leiz, Steffen and Juliette, Kali and Richardson, Randal and Yang, Ying and Zhang, Yuehua and Wang, Minghui and Wang, Jia and Wang, Xiaodong and Platzer, Konrad and Donkervoort, Sandra and B{\"o}nnemann, Carsten G and Wagner, Matias and Issa, Mahmoud Y and Elbendary, Hasnaa M and Stanley, Valentina and Maroofian, Reza and Gleeson, Joseph G and Zaki, MAH S and Senderek, Jan and Pandey, Udai Bhan} } @article {924, title = {Mutations in Spliceosomal Genes PPIL1 and PRP17 Cause Neurodegenerative Pontocerebellar Hypoplasia with Microcephaly.}, journal = {Neuron}, volume = {109}, year = {2021}, month = {2021 01 20}, pages = {241-256.e9}, abstract = {

Autosomal-recessive cerebellar hypoplasia and ataxia constitute a group of heterogeneous brain disorders caused by disruption of several fundamental cellular processes. Here, we identified 10 families showing a neurodegenerative condition involving pontocerebellar hypoplasia with microcephaly (PCHM). Patients harbored biallelic mutations in genes encoding the spliceosome components Peptidyl-Prolyl Isomerase Like-1 (PPIL1) or Pre-RNA Processing-17 (PRP17). Mouse knockouts of either gene were lethal in early embryogenesis, whereas PPIL1 patient mutation knockin mice showed neuron-specific apoptosis. Loss of either protein affected splicing integrity, predominantly affecting short and high GC-content introns and genes involved in brain disorders. PPIL1 and PRP17 form an active isomerase-substrate interaction, but we found that isomerase activity is not critical for function. Thus, we establish disrupted splicing integrity and "major spliceosome-opathies" as a new mechanism underlying PCHM and neurodegeneration and uncover a non-enzymatic function of a spliceosomal proline isomerase.

}, keywords = {Amino Acid Sequence, Animals, Cell Cycle Proteins, Cerebellar Diseases, Cohort Studies, Female, Gene Knockout Techniques, HEK293 Cells, Heredodegenerative Disorders, Nervous System, Humans, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Microcephaly, Mutation, Pedigree, Peptidylprolyl Isomerase, Protein Structure, Secondary, Protein Structure, Tertiary, RNA Splicing Factors, Spliceosomes}, issn = {1097-4199}, doi = {10.1016/j.neuron.2020.10.035}, author = {Chai, Guoliang and Webb, Alice and Li, Chen and Antaki, Danny and Lee, Sangmoon and Breuss, Martin W and Lang, Nhi and Stanley, Valentina and Anzenberg, Paula and Yang, Xiaoxu and Marshall, Trevor and Gaffney, Patrick and Wierenga, Klaas J and Chung, Brian Hon-Yin and Tsang, Mandy Ho-Yin and Pais, Lynn S and Lovgren, Alysia Kern and VanNoy, Grace E and Rehm, Heidi L and Mirzaa, Ghayda and Leon, Eyby and Diaz, Jullianne and Neumann, Alexander and Kalverda, Arnout P and Manfield, Iain W and Parry, David A and Logan, Clare V and Johnson, Colin A and Bonthron, David T and Valleley, Elizabeth M A and Issa, Mahmoud Y and Abdel-Ghafar, Sherif F and Abdel-Hamid, Mohamed S and Jennings, Patricia and Zaki, MAH S and Sheridan, Eamonn and Gleeson, Joseph G} } @article {949, title = {A relatively common homozygous TRAPPC4 splicing variant is associated with an early-infantile neurodegenerative syndrome.}, journal = {Eur J Hum Genet}, volume = {29}, year = {2021}, month = {2021 Feb}, pages = {271-279}, abstract = {

Trafficking protein particle (TRAPP) complexes, which include the TRAPPC4 protein, regulate membrane trafficking between lipid organelles in a process termed vesicular tethering. TRAPPC4 was recently implicated in a recessive neurodevelopmental condition in four unrelated families due to a shared c.454+3A>G splice variant. Here, we report 23 patients from 17 independent families with an early-infantile-onset neurodegenerative presentation, where we also identified the homozygous variant hg38:11:119020256 A>G (NM_016146.5:c.454+3A>G) in TRAPPC4 through exome or genome sequencing. No other clinically relevant TRAPPC4 variants were identified among any of over 10,000 patients with neurodevelopmental conditions. We found the carrier frequency of TRAPPC4 c.454+3A>G was 2.4-5.4 per 10,000 healthy individuals. Affected individuals with the homozygous TRAPPC4 c.454+3A>G variant showed profound psychomotor delay, developmental regression, early-onset epilepsy, microcephaly and progressive spastic tetraplegia. Based upon RNA sequencing, the variant resulted in partial exon 3 skipping and generation of an aberrant transcript owing to use of a downstream cryptic splice donor site, predicting a premature stop codon and nonsense mediated decay. These data confirm the pathogenicity of the TRAPPC4 c.454+3A>G variant, and refine the clinical presentation of TRAPPC4-related encephalopathy.

}, issn = {1476-5438}, doi = {10.1038/s41431-020-00717-5}, author = {Ghosh, Shereen G and Scala, Marcello and Beetz, Christian and Helman, Guy and Stanley, Valentina and Yang, Xiaoxu and Breuss, Martin W and Mazaheri, Neda and Selim, Laila and Hadipour, Fatemeh and Pais, Lynn and Stutterd, Chloe A and Karageorgou, Vasiliki and Begtrup, Amber and Crunk, Amy and Juusola, Jane and Willaert, Rebecca and Flore, Leigh A and Kennelly, Kelly and Spencer, Christopher and Brown, Martha and Trapane, Pamela and Hurst, Anna C E and Lane Rutledge, S and Goodloe, Dana H and McDonald, Marie T and Shashi, Vandana and Schoch, Kelly and Tomoum, Hoda and Zaitoun, Raghda and Hadipour, Zahra and Galehdari, Hamid and Pagnamenta, Alistair T and Mojarrad, Majid and Sedaghat, Alireza and Dias, Patr{\'\i}cia and Quintas, Sofia and Eslahi, Atiyeh and Shariati, Gholamreza and Bauer, Peter and Simons, Cas and Houlden, Henry and Issa, Mahmoud Y and Zaki, MAH S and Maroofian, Reza and Gleeson, Joseph G} } @article {806, title = {Biallelic loss of function variants in SYT2 cause a treatable congenital onset presynaptic myasthenic syndrome.}, journal = {Am J Med Genet A}, volume = {182}, year = {2020}, month = {2020 10}, pages = {2272-2283}, abstract = {

Synaptotagmins are integral synaptic vesicle membrane proteins that function as calcium sensors and regulate neurotransmitter release at the presynaptic nerve terminal. Synaptotagmin-2 (SYT2), is the major isoform expressed at the neuromuscular junction. Recently, dominant missense variants in SYT2 have been reported as a rare cause of distal motor neuropathy and myasthenic syndrome, manifesting with stable or slowly progressive distal weakness of variable severity along with presynaptic NMJ impairment. These variants are thought to have a dominant-negative effect on synaptic vesicle exocytosis, although the precise pathomechanism remains to be elucidated. Here we report seven patients of five families, with biallelic loss of function variants in SYT2, clinically manifesting with a remarkably consistent phenotype of severe congenital onset hypotonia and weakness, with variable degrees of respiratory involvement. Electrodiagnostic findings were consistent with a presynaptic congenital myasthenic syndrome (CMS) in some. Treatment with an acetylcholinesterase inhibitor pursued in three patients showed clinical improvement with increased strength and function. This series further establishes SYT2 as a CMS-disease gene and expands its clinical and genetic spectrum to include recessive loss-of-function variants, manifesting as a severe congenital onset presynaptic CMS with potential treatment implications.

}, keywords = {Adolescent, Child, Child, Preschool, Female, Genetic Predisposition to Disease, Humans, Male, Muscle Hypotonia, Muscle Weakness, Mutation, Missense, Myasthenic Syndromes, Congenital, Pedigree, Phenotype, Synaptic Transmission, Synaptotagmin II}, issn = {1552-4833}, doi = {10.1002/ajmg.a.61765}, author = {Donkervoort, Sandra and Mohassel, Payam and Laugwitz, Lucia and Zaki, MAH S and Kamsteeg, Erik-Jan and Maroofian, Reza and Chao, Katherine R and Verschuuren-Bemelmans, Corien C and Horber, Veronka and Fock, Annemarie J M and McCarty, Riley M and Jain, Minal S and Biancavilla, Victoria and McMacken, Grace and Nalls, Matthew and Voermans, Nicol C and Elbendary, Hasnaa M and Snyder, Molly and Cai, Chunyu and Lehky, Tanya J and Stanley, Valentina and Iannaccone, Susan T and Foley, A Reghan and Lochm{\"u}ller, Hanns and Gleeson, Joseph and Houlden, Henry and Haack, Tobias B and Horvath, Rita and B{\"o}nnemann, Carsten G} } @article {804, title = {Loss of NARS1 impairs progenitor proliferation in cortical brain organoids and leads to microcephaly.}, journal = {Nat Commun}, volume = {11}, year = {2020}, month = {2020 08 12}, pages = {4038}, abstract = {

Asparaginyl-tRNA synthetase1 (NARS1) is a member of the ubiquitously expressed cytoplasmic Class IIa family of tRNA synthetases required for protein translation. Here, we identify biallelic missense and frameshift mutations in NARS1 in seven patients from three unrelated families with microcephaly and neurodevelopmental delay. Patient cells show reduced NARS1 protein, impaired NARS1 activity and impaired global protein synthesis. Cortical brain organoid modeling shows reduced proliferation of radial glial cells (RGCs), leading to smaller organoids characteristic of microcephaly. Single-cell analysis reveals altered constituents of both astrocytic and RGC lineages, suggesting a requirement for NARS1 in RGC proliferation. Our findings demonstrate that NARS1 is required to meet protein synthetic needs and to support RGC proliferation in human brain development.

}, keywords = {Adolescent, Adult, Aspartate-tRNA Ligase, Base Sequence, Cell Differentiation, Cell Proliferation, Cell Size, Cell Survival, Cerebral Cortex, Child, Family, Female, Fibroblasts, HEK293 Cells, Humans, Induced Pluripotent Stem Cells, Ki-67 Antigen, Male, Microcephaly, Mutation, Neural Stem Cells, Neuroglia, Organoids, Pedigree, RNA, Transfer, Amino Acyl, Young Adult}, issn = {2041-1723}, doi = {10.1038/s41467-020-17454-4}, author = {Wang, Lu and Li, Zhen and Sievert, David and Smith, Desir{\'e}e E C and Mendes, Marisa I and Chen, Dillon Y and Stanley, Valentina and Ghosh, Shereen and Wang, Yulu and Kara, Majdi and Aslanger, Ayca Dilruba and Rosti, Rasim O and Houlden, Henry and Salomons, Gajja S and Gleeson, Joseph G} } @article {828, title = {Loss of the neural-specific BAF subunit ACTL6B relieves repression of early response genes and causes recessive autism.}, journal = {Proc Natl Acad Sci U S A}, volume = {117}, year = {2020}, month = {2020 05 05}, pages = {10055-10066}, abstract = {

Synaptic activity in neurons leads to the rapid activation of genes involved in mammalian behavior. ATP-dependent chromatin remodelers such as the BAF complex contribute to these responses and are generally thought to activate transcription. However, the mechanisms keeping such "early activation" genes silent have been a mystery. In the course of investigating Mendelian recessive autism, we identified six families with segregating loss-of-function mutations in the neuronal BAF (nBAF) subunit (originally named ). Accordingly, was the most significantly mutated gene in the Simons Recessive Autism Cohort. At least 14 subunits of the nBAF complex are mutated in autism, collectively making it a major contributor to autism spectrum disorder (ASD). Patient mutations destabilized ACTL6B protein in neurons and rerouted dendrites to the wrong glomerulus in the fly olfactory system. Humans and mice lacking showed corpus callosum hypoplasia, indicating a conserved role for in facilitating neural connectivity. knockout mice on two genetic backgrounds exhibited ASD-related behaviors, including social and memory impairments, repetitive behaviors, and hyperactivity. Surprisingly, mutation of relieved repression of early response genes including AP1 transcription factors (, , , and ), increased chromatin accessibility at AP1 binding sites, and transcriptional changes in late response genes associated with early response transcription factor activity. loss is thus an important cause of recessive ASD, with impaired neuron-specific chromatin repression indicated as a potential mechanism.

}, keywords = {Actins, Adenosine Triphosphate, Animals, Autism Spectrum Disorder, Behavior, Animal, Chromatin, Chromatin Assembly and Disassembly, Chromosomal Proteins, Non-Histone, Chromosome Pairing, Corpus Callosum, Dendrites, Disease Models, Animal, DNA-Binding Proteins, Gene Expression Regulation, Hippocampus, Humans, Mice, Mice, Knockout, Mutation, Neurons, Transcription Factors}, issn = {1091-6490}, doi = {10.1073/pnas.1908238117}, author = {Wenderski, Wendy and Wang, Lu and Krokhotin, Andrey and Walsh, Jessica J and Li, Hongjie and Shoji, Hirotaka and Ghosh, Shereen and George, Renee D and Miller, Erik L and Elias, Laura and Gillespie, Mark A and Son, Esther Y and Staahl, Brett T and Baek, Seung Tae and Stanley, Valentina and Moncada, Cynthia and Shipony, Zohar and Linker, Sara B and Marchetto, Maria C N and Gage, Fred H and Chen, Dillon and Sultan, Tipu and Zaki, MAH S and Ranish, Jeffrey A and Miyakawa, Tsuyoshi and Luo, Liqun and Malenka, Robert C and Crabtree, Gerald R and Gleeson, Joseph G} } @article {826, title = {Molecular diagnosis in recessive pediatric neurogenetic disease can help reduce disease recurrence in families.}, journal = {BMC Med Genomics}, volume = {13}, year = {2020}, month = {2020 05 13}, pages = {68}, abstract = {

BACKGROUND: The causes for thousands of individually rare recessive diseases have been discovered since the adoption of next generation sequencing (NGS). Following the molecular diagnosis in older children in a family, parents could use this information to opt for fetal genotyping in subsequent pregnancies, which could inform decisions about elective termination of pregnancy. The use of NGS diagnostic sequencing in families has not been demonstrated to yield benefit in subsequent pregnancies to reduce recurrence. Here we evaluated whether genetic diagnosis in older children in families supports reduction in recurrence of recessive neurogenetic disease.

METHODS: Retrospective study involving families with a child with a recessive pediatric brain disease (rPBD) that underwent NGS-based molecular diagnosis. Prenatal molecular testing was offered to couples in which a molecular diagnosis was made, to help couples seeking to prevent recurrence. With this information, families made decisions about elective termination. Pregnancies that were carried to term were assessed for the health of child and mother, and compared with historic recurrence risk of recessive disease.

RESULTS: Between 2010 and 2016, 1172 families presented with a child a likely~rPBD, 526 families received a molecular diagnosis, 91 families returned to the clinic with 101 subsequent pregnancies, and 84 opted for fetal genotyping. Sixty tested negative for recurrence for the biallelic mutation~in the fetus, and all, except for one spontaneous abortion, carried to term, and were unaffected at follow-up. Of 24 that genotyped positive~for~the biallelic mutation, 16 were electively terminated, and 8 were carried to term and showed features of disease similar to that of the older~affected sibling(s). Among the 101 pregnancies, disease recurrence in living offspring deviated from the expected 25\% to the observed 12\% ([95\% CI 0{\textperiodcentered}04 to 0{\textperiodcentered}20], p = 0{\textperiodcentered}011).

CONCLUSIONS: Molecular diagnosis in an older child, coupled with prenatal fetal genotyping in subsequent pregnancies and genetic counselling, allows families to make informed decisions to reduce recessive neurogenetic disease recurrence.

}, keywords = {Child, Preschool, Female, Genes, Recessive, Genetic Markers, Genetic Predisposition to Disease, Genetic Testing, Genotype, High-Throughput Nucleotide Sequencing, Humans, Infant, Infant, Newborn, Male, Mutation, Nervous System Diseases, Pedigree, Pregnancy, Prenatal Diagnosis, Recurrence, Retrospective Studies}, issn = {1755-8794}, doi = {10.1186/s12920-020-0714-1}, author = {Issa, Mahmoud Y and Chechlacz, Zinayida and Stanley, Valentina and George, Renee D and McEvoy-Venneri, Jennifer and Belandres, Denice and Elbendary, Hasnaa M and Gaber, Khaled R and Nabil, Ahmed and Abdel-Hamid, Mohamed S and Zaki, MAH S and Gleeson, Joseph G} } @article {928, title = {Novel congenital disorder of O-linked glycosylation caused by GALNT2 loss of function.}, journal = {Brain}, volume = {143}, year = {2020}, month = {2020 04 01}, pages = {1114-1126}, abstract = {

Congenital disorders of glycosylation are a growing group of rare genetic disorders caused by deficient protein and lipid glycosylation. Here, we report the clinical, biochemical, and molecular features of seven patients from four families with GALNT2-congenital disorder of glycosylation (GALNT2-CDG), an O-linked glycosylation disorder. GALNT2 encodes the Golgi-localized polypeptide N-acetyl-d-galactosamine-transferase 2 isoenzyme. GALNT2 is widely expressed in most cell types and directs initiation of mucin-type protein O-glycosylation. All patients showed loss of O-glycosylation of apolipoprotein C-III, a non-redundant substrate for GALNT2. Patients with GALNT2-CDG generally exhibit a syndrome characterized by global developmental delay, intellectual disability with language deficit, autistic features, behavioural abnormalities, epilepsy, chronic insomnia, white matter changes on brain MRI, dysmorphic features, decreased stature, and decreased high density lipoprotein cholesterol levels. Rodent (mouse and rat) models of GALNT2-CDG recapitulated much of the human phenotype, including poor growth and neurodevelopmental abnormalities. In behavioural studies, GALNT2-CDG mice demonstrated cerebellar motor deficits, decreased sociability, and impaired sensory integration and processing. The multisystem nature of phenotypes in patients and rodent models of GALNT2-CDG suggest that there are multiple non-redundant protein substrates of GALNT2 in various tissues, including brain, which are critical to normal growth and development.

}, keywords = {Adolescent, Animals, Apolipoprotein C-III, Child, Child, Preschool, Developmental Disabilities, Female, Glycosylation, Humans, Loss of Function Mutation, Male, Mice, N-Acetylgalactosaminyltransferases, Pedigree, Rats, Young Adult}, issn = {1460-2156}, doi = {10.1093/brain/awaa063}, author = {Zilmer, Monica and Edmondson, Andrew C and Khetarpal, Sumeet A and Alesi, Viola and Zaki, MAH S and Rostasy, Kevin and Madsen, Camilla G and Lepri, Francesca R and Sinibaldi, Lorenzo and Cusmai, Raffaella and Novelli, Antonio and Issa, Mahmoud Y and Fenger, Christina D and Abou Jamra, Rami and Reutter, Heiko and Briuglia, Silvana and Agolini, Emanuele and Hansen, Lars and Pet{\"a}j{\"a}-Repo, Ulla E and Hintze, John and Raymond, Kimiyo M and Liedtke, Kristen and Stanley, Valentina and Musaev, Damir and Gleeson, Joseph G and Vitali, Cecilia and O{\textquoteright}Brien, W Timothy and Gardella, Elena and Rubboli, Guido and Rader, Daniel J and Schjoldager, Katrine T and M{\o}ller, Rikke S} } @article {956, title = {Recurrent homozygous damaging mutation in , encoding a protein disulfide isomerase, in four families with microlissencephaly.}, journal = {J Med Genet}, volume = {57}, year = {2020}, month = {2020 04}, pages = {274-282}, abstract = {

BACKGROUND: Protein disulfide isomerase (PDI) proteins are part of the thioredoxin protein superfamily. PDIs are involved in the formation and rearrangement of disulfide bonds between cysteine residues during protein folding in the endoplasmic reticulum and are implicated in stress response pathways.

METHODS: Eight children from four consanguineous families residing in distinct geographies within the Middle East and Central Asia were recruited for study. All probands showed structurally similar microcephaly with lissencephaly (microlissencephaly) brain malformations. DNA samples from each family underwent whole exome sequencing, assessment for repeat expansions and confirmatory segregation analysis.

RESULTS: An identical homozygous variant in (c.500G>A), encoding thioredoxin-related transmembrane protein 2, segregated with disease in all four families. This variant changed the last coding base of exon 6, and impacted mRNA stability. All patients presented with microlissencephaly, global developmental delay, intellectual disability and epilepsy. While is an activator of cellular repeat expansion toxicity, patients showed no evidence of repeat expansions.

CONCLUSION: The c.500G>A allele associates with recessive microlissencephaly, and patients show no evidence of expansions. is the first PDI implicated in a recessive disease, suggesting a protein isomerisation defect in microlissencephaly.

}, keywords = {Amino Acid Sequence, Child, Child, Preschool, Consanguinity, Endoplasmic Reticulum, Exons, Female, Genetic Predisposition to Disease, Homozygote, Humans, Male, Membrane Proteins, Microcephaly, Mutation, Protein Disulfide-Isomerases, Protein Folding, Thioredoxins, Whole Exome Sequencing}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2019-106409}, author = {Ghosh, Shereen Georges and Wang, Lu and Breuss, Martin W and Green, Joshua D and Stanley, Valentina and Yang, Xiaoxu and Ross, Danica and Traynor, Bryan J and Alhashem, Amal M and Azam, Matloob and Selim, Laila and Bastaki, Laila and Elbastawisy, Hanan I and Temtamy, Samia and Zaki, MAH and Gleeson, Joseph G} } @article {654, title = {Bi-allelic Mutations in FAM149B1 Cause Abnormal Primary Cilium and a Range of Ciliopathy Phenotypes in Humans.}, journal = {Am J Hum Genet}, volume = {104}, year = {2019}, month = {2019 Apr 04}, pages = {731-737}, abstract = {

Ciliopathies are clinical disorders of the primary cilium with widely recognized phenotypic and genetic heterogeneity. In two Arab consanguineous families, we mapped a ciliopathy phenotype that most closely matches Joubert syndrome (hypotonia, developmental delay, typical facies, oculomotor apraxia, polydactyly, and subtle posterior fossa abnormalities) to a single locus in which a founder homozygous truncating variant in FAM149B1 was identified by exome sequencing. We subsequently identified a third Arab consanguineous multiplex family in which the phenotype of Joubert syndrome/oral-facial-digital syndrome (OFD VI) was found to co-segregate with the same founder variant in FAM149B1. Independently, autozygosity mapping and exome sequencing in a consanguineous Turkish family with Joubert syndrome highlighted a different homozygous truncating variant in the same gene. FAM149B1 encodes a protein of unknown function. Mutant fibroblasts were found to have normal ciliogenesis potential. However, distinct cilia-related abnormalities were observed in these cells: abnormal accumulation IFT complex at the distal tips of the cilia, which assumed bulbous appearance, increased length of the primary cilium, and dysregulated SHH signaling. We conclude that FAM149B1 is required for normal ciliary biology and that its deficiency results in a range of ciliopathy phenotypes in humans along the spectrum of Joubert syndrome.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.02.018}, author = {Shaheen, Ranad and Jiang, Nan and Alzahrani, Fatema and Ewida, Nour and Al-Sheddi, Tarfa and Alobeid, Eman and Musaev, Damir and Stanley, Valentina and Hashem, Mais and Ibrahim, Niema and Abdulwahab, Firdous and Alshenqiti, Abduljabbar and Sonmez, Fatma Mujgan and Saqati, Nadia and Alzaidan, Hamad and Al-Qattan, Mohammad M and Al-Mohanna, Futwan and Gleeson, Joseph G and Alkuraya, Fowzan S} } @article {574, title = {Biallelic mutations in valyl-tRNA synthetase gene VARS are associated with a progressive neurodevelopmental epileptic encephalopathy.}, journal = {Nat Commun}, volume = {10}, year = {2019}, month = {2019 02 12}, pages = {707}, abstract = {

Aminoacyl-tRNA synthetases (ARSs) function to transfer amino acids to cognate tRNA molecules, which are required for protein translation. To date, biallelic mutations in 31 ARS genes are known to cause recessive, early-onset severe multi-organ diseases. VARS encodes the only known valine cytoplasmic-localized aminoacyl-tRNA synthetase. Here, we report seven patients from five unrelated families with five different biallelic missense variants in VARS. Subjects present with a range of global developmental delay, epileptic encephalopathy and primary or progressive microcephaly. Longitudinal assessment demonstrates progressive cortical atrophy and white matter volume loss. Variants map to the VARS tRNA binding domain and adjacent to the anticodon domain, and disrupt highly conserved residues. Patient primary cells show intact VARS protein but reduced enzymatic activity, suggesting partial loss of function. The implication of VARS in pediatric neurodegeneration broadens the spectrum of human diseases due to mutations in tRNA synthetase genes.

}, keywords = {Alleles, Anticodon, Child, Child, Preschool, Disease Progression, Epilepsy, Female, Genetic Predisposition to Disease, Humans, Longitudinal Studies, Loss of Function Mutation, Male, Microcephaly, Models, Molecular, Mutation, Neurodevelopmental Disorders, Pedigree, Protein Biosynthesis, Protein Interaction Domains and Motifs, RNA, Transfer, Valine-tRNA Ligase, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {2041-1723}, doi = {10.1038/s41467-018-07067-3}, author = {Friedman, Jennifer and Smith, Desiree E and Issa, Mahmoud Y and Stanley, Valentina and Wang, Rengang and Mendes, Marisa I and Wright, Meredith S and Wigby, Kristen and Hildreth, Amber and Crawford, John R and Koehler, Alanna E and Chowdhury, Shimul and Nahas, Shareef and Zhai, Liting and Xu, Zhiwen and Lo, Wing-Sze and James, Kiely N and Musaev, Damir and Accogli, Andrea and Guerrero, Kether and Tran, Luan T and Omar, Tarek E I and Ben-Omran, Tawfeg and Dimmock, David and Kingsmore, Stephen F and Salomons, Gajja S and Zaki, Maha S and Bernard, Genevi{\`e}ve and Gleeson, Joseph G} } @article {716, title = {Homozygous Missense Variants in NTNG2, Encoding a Presynaptic Netrin-G2 Adhesion Protein, Lead to a Distinct Neurodevelopmental Disorder.}, journal = {Am J Hum Genet}, volume = {105}, year = {2019}, month = {2019 Nov 07}, pages = {1048-1056}, abstract = {

NTNG2 encodes netrin-G2, a membrane-anchored protein implicated in the molecular organization of neuronal circuitry and synaptic organization and diversification in vertebrates. In this study, through a combination of exome sequencing and autozygosity mapping, we have identified 16 individuals (from seven unrelated families) with ultra-rare homozygous missense variants in NTNG2; these individuals present with shared features of a neurodevelopmental disorder consisting of global developmental delay, severe to profound intellectual disability, muscle weakness and abnormal tone, autistic features, behavioral abnormalities, and variable dysmorphisms. The variants disrupt highly conserved residues across the protein. Functional experiments, including in silico analysis of the protein structure, in~vitro assessment of cell surface expression, and in~vitro knockdown, revealed potential mechanisms of pathogenicity of the variants, including loss of protein function and decreased neurite outgrowth. Our data indicate that appropriate expression of NTNG2 plays an important role in neurotypical development.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.09.025}, author = {Dias, Caroline M and Punetha, Jaya and Zheng, C{\'e}line and Mazaheri, Neda and Rad, Abolfazl and Efthymiou, Stephanie and Petersen, Andrea and Dehghani, Mohammadreza and Pehlivan, Davut and Partlow, Jennifer N and Posey, Jennifer E and Salpietro, Vincenzo and Gezdirici, Alper and Malamiri, Reza Azizi and Al Menabawy, Nihal M and Selim, Laila A and Vahidi Mehrjardi, Mohammad Yahya and Banu, Selina and Polla, Daniel L and Yang, Edward and Rezazadeh Varaghchi, Jamileh and Mitani, Tadahiro and van Beusekom, Ellen and Najafi, Maryam and Sedaghat, Alireza and Keller-Ramey, Jennifer and Durham, Leslie and Coban-Akdemir, Zeynep and Karaca, Ender and Orlova, Valeria and Schaeken, Lieke L M and Sherafat, Amir and Jhangiani, Shalini N and Stanley, Valentina and Shariati, Gholamreza and Galehdari, Hamid and Gleeson, Joseph G and Walsh, Christopher A and Lupski, James R and Seiradake, Elena and Houlden, Henry and van Bokhoven, Hans and Maroofian, Reza} } @article {719, title = {Loss of SMPD4 Causes a Developmental Disorder Characterized by Microcephaly and Congenital Arthrogryposis.}, journal = {Am J Hum Genet}, volume = {105}, year = {2019}, month = {2019 Oct 03}, pages = {689-705}, abstract = {

Sphingomyelinases generate ceramide from sphingomyelin as a second messenger in intracellular signaling pathways involved in cell proliferation, differentiation, or apoptosis. Children from 12 unrelated families presented with microcephaly, simplified gyral pattern of the cortex, hypomyelination, cerebellar hypoplasia, congenital arthrogryposis, and early fetal/postnatal demise. Genomic analysis revealed bi-allelic loss-of-function variants in SMPD4, coding for the neutral sphingomyelinase-3 (nSMase-3/SMPD4). Overexpression of human Myc-tagged SMPD4 showed localization both to the outer nuclear envelope and the ER and additionally revealed interactions with several nuclear pore complex proteins by proteomics analysis. Fibroblasts from affected individuals showed ER cisternae abnormalities, suspected for increased autophagy, and were more susceptible to apoptosis under stress conditions, while treatment with siSMPD4 caused delayed cell cycle progression. Our data show that SMPD4 links homeostasis of membrane sphingolipids to cell fate by regulating the cross-talk between the ER and the outer nuclear envelope, while its loss reveals a pathogenic mechanism in microcephaly.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.08.006}, author = {Magini, Pamela and Smits, Daphne J and Vandervore, Laura and Schot, Rachel and Columbaro, Marta and Kasteleijn, Esmee and van der Ent, Mees and Palombo, Flavia and Lequin, Maarten H and Dremmen, Marjolein and de Wit, Marie Claire Y and Severino, Mariasavina and Divizia, Maria Teresa and Striano, Pasquale and Ordonez-Herrera, Natalia and Alhashem, Amal and Al Fares, Ahmed and Al Ghamdi, Malak and Rolfs, Arndt and Bauer, Peter and Demmers, Jeroen and Verheijen, Frans W and Wilke, Martina and van Slegtenhorst, Marjon and van der Spek, Peter J and Seri, Marco and Jansen, Anna C and Stottmann, Rolf W and Hufnagel, Robert B and Hopkin, Robert J and Aljeaid, Deema and Wiszniewski, Wojciech and Gawlinski, Pawel and Laure-Kamionowska, Milena and Alkuraya, Fowzan S and Akleh, Hanah and Stanley, Valentina and Musaev, Damir and Gleeson, Joseph G and Zaki, Maha S and Brunetti-Pierri, Nicola and Cappuccio, Gerarda and Davidov, Bella and Basel-Salmon, Lina and Bazak, Lily and Shahar, Noa Ruhrman and Bertoli-Avella, Aida and Mirzaa, Ghayda M and Dobyns, William B and Pippucci, Tommaso and Fornerod, Maarten and Mancini, Grazia M S} } @article {520, title = {Biallelic Mutations in ADPRHL2, Encoding ADP-Ribosylhydrolase 3, Lead to a Degenerative Pediatric Stress-Induced Epileptic Ataxia Syndrome.}, journal = {Am J Hum Genet}, volume = {103}, year = {2018}, month = {2018 09 06}, pages = {431-439}, abstract = {

ADP-ribosylation, the addition of poly-ADP ribose (PAR) onto proteins, is a response signal to cellular challenges, such as excitotoxicity or oxidative stress. This process is catalyzed by a group of enzymes referred to as poly(ADP-ribose) polymerases (PARPs). Because the accumulation of proteins with this modification results in cell death, its negative regulation restores cellular homeostasis: a process mediated by poly-ADP ribose glycohydrolases (PARGs) and ADP-ribosylhydrolase proteins (ARHs). Using linkage analysis and exome or genome sequencing, we identified recessive inactivating mutations in ADPRHL2 in six families. Affected individuals exhibited a pediatric-onset neurodegenerative disorder with progressive brain atrophy, developmental regression, and seizures in association with periods of stress, such as infections. Loss of the Drosophila paralog Parg showed lethality in response to oxidative challenge that was rescued by human ADPRHL2, suggesting functional conservation. Pharmacological inhibition of PARP also rescued the phenotype, suggesting the possibility of postnatal treatment for this genetic condition.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.07.010}, author = {Ghosh, Shereen G and Becker, Kerstin and Huang, He and Dixon-Salazar, Tracy and Chai, Guoliang and Salpietro, Vincenzo and Al-Gazali, Lihadh and Waisfisz, Quinten and Wang, Haicui and Vaux, Keith K and Stanley, Valentina and Manole, Andreea and Akpulat, Ugur and Weiss, Marjan M and Efthymiou, Stephanie and Hanna, Michael G and Minetti, Carlo and Striano, Pasquale and Pisciotta, Livia and De Grandis, Elisa and Altm{\"u}ller, Janine and N{\"u}rnberg, Peter and Thiele, Holger and Yis, Uluc and Okur, Tuncay Derya and Polat, Ayse Ipek and Amiri, Nafise and Doosti, Mohammad and Karimani, Ehsan Ghayoor and Toosi, Mehran B and Haddad, Gabriel and Karakaya, Mert and Wirth, Brunhilde and van Hagen, Johanna M and Wolf, Nicole I and Maroofian, Reza and Houlden, Henry and Cirak, Sebahattin and Gleeson, Joseph G} } @article {452, title = {Biallelic variants in KIF14 cause intellectual disability with microcephaly.}, journal = {Eur J Hum Genet}, volume = {26}, year = {2018}, month = {2018 03}, pages = {330-339}, abstract = {

Kinesin proteins are critical for various cellular functions such as intracellular transport and cell division, and many members of the family have been linked to monogenic disorders and cancer. We report eight individuals with intellectual disability and microcephaly from four unrelated families with parental consanguinity. In the affected individuals of each family, homozygosity for likely pathogenic variants in KIF14 were detected; two loss-of-function (p.Asn83Ilefs*3 and p.Ser1478fs), and two missense substitutions (p.Ser841Phe and p.Gly459Arg). KIF14 is a mitotic motor protein that is required for spindle localization of the mitotic citron rho-interacting kinase, CIT, also mutated in microcephaly. Our results demonstrate the involvement of KIF14 in development and reveal a wide phenotypic variability ranging from fetal lethality to moderate developmental delay and microcephaly.

}, keywords = {Child, Child, Preschool, Female, Humans, Intellectual Disability, Kinesin, Loss of Function Mutation, Microcephaly, Mutation, Missense, Oncogene Proteins, Pedigree, Phenotype, Protein Domains, Syndrome}, issn = {1476-5438}, doi = {10.1038/s41431-017-0088-9}, author = {Makrythanasis, Periklis and Maroofian, Reza and Stray-Pedersen, Asbj{\o}rg and Musaev, Damir and Zaki, Maha S and Mahmoud, Iman G and Selim, Laila and Elbadawy, Amera and Jhangiani, Shalini N and Coban Akdemir, Zeynep H and Gambin, Tomasz and Sorte, Hanne S and Heiberg, Arvid and McEvoy-Venneri, Jennifer and James, Kiely N and Stanley, Valentina and Belandres, Denice and Guipponi, Michel and Santoni, Federico A and Ahangari, Najmeh and Tara, Fatemeh and Doosti, Mohammad and Iwaszkiewicz, Justyna and Zoete, Vincent and Backe, Paul Hoff and Hamamy, Hanan and Gleeson, Joseph G and Lupski, James R and Karimiani, Ehsan Ghayoor and Antonarakis, Stylianos E} } @article {500, title = {Genetic variants in components of the NALCN-UNC80-UNC79 ion channel complex cause a broad clinical phenotype (NALCN channelopathies).}, journal = {Hum Genet}, volume = {137}, year = {2018}, month = {2018 Sep}, pages = {753-768}, abstract = {

NALCN is a conserved cation channel, which conducts a permanent sodium leak current and regulates resting membrane potential and neuronal excitability. It is part of a large ion channel complex, the "NALCN channelosome", consisting of multiple proteins including UNC80 and UNC79. The predominant neuronal expression pattern and its function suggest an important role in neuronal function and disease. So far, biallelic NALCN and UNC80 variants have been described in a small number of individuals leading to infantile hypotonia, psychomotor retardation, and characteristic facies 1 (IHPRF1, OMIM 615419) and 2 (IHPRF2, OMIM 616801), respectively. Heterozygous de novo NALCN missense variants in the S5/S6 pore-forming segments lead to congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, OMIM 616266) with some clinical overlap. In this study, we present detailed clinical information of 16 novel individuals with biallelic NALCN variants, 1 individual with a heterozygous de novo NALCN missense variant and an interesting clinical phenotype without contractures, and 12 individuals with biallelic UNC80 variants. We report for the first time a missense NALCN variant~located in the predicted S6 pore-forming unit inherited in an autosomal-recessive manner leading to mild IHPRF1. We show evidence of clinical variability, especially among IHPRF1-affected individuals, and discuss differences between the IHPRF1- and IHPRF2 phenotypes. In summary, we provide a comprehensive overview of IHPRF1 and IHPRF2 phenotypes based on the largest cohort of individuals reported so far and provide additional insights into the clinical phenotypes of these neurodevelopmental diseases to help improve counseling of affected families.

}, keywords = {Adolescent, Adult, Carrier Proteins, Channelopathies, Child, Child, Preschool, Developmental Disabilities, Female, Genetic Markers, Genetic Variation, Humans, Infant, Infant, Newborn, Male, Membrane Proteins, Phenotype, Sodium Channels, Young Adult}, issn = {1432-1203}, doi = {10.1007/s00439-018-1929-5}, author = {Bramswig, Nuria C and Bertoli-Avella, Aida M and Albrecht, Beate and Al Aqeel, Aida I and Alhashem, Amal and Al-Sannaa, Nouriya and Bah, Maissa and Br{\"o}hl, Katharina and Depienne, Christel and Dorison, Nathalie and Doummar, Diane and Ehmke, Nadja and Elbendary, Hasnaa M and Gorokhova, Svetlana and H{\'e}ron, Delphine and Horn, Denise and James, Kiely and Keren, Boris and Kuechler, Alma and Ismail, Samira and Issa, Mahmoud Y and Marey, Isabelle and Mayer, Mich{\`e}le and McEvoy-Venneri, Jennifer and Megarbane, Andre and Mignot, Cyril and Mohamed, Sarar and Nava, Caroline and Philip, Nicole and Ravix, Cecile and Rolfs, Arndt and Sadek, Abdelrahim Abdrabou and Segebrecht, Lara and Stanley, Valentina and Trautman, Camille and Valence, Stephanie and Villard, Laurent and Wieland, Thomas and Engels, Hartmut and Strom, Tim M and Zaki, Maha S and Gleeson, Joseph G and L{\"u}decke, Hermann-Josef and Bauer, Peter and Wieczorek, Dagmar} } @article {494, title = {A homozygous founder mutation in associates with a neurodevelopmental disorder characterised by microcephaly, epilepsy and autistic features.}, journal = {J Med Genet}, volume = {55}, year = {2018}, month = {2018 01}, pages = {48-54}, abstract = {

BACKGROUND: Transport protein particle (TRAPP) is a multisubunit complex that regulates membrane trafficking through the Golgi apparatus. The clinical phenotype associated with mutations in various TRAPP subunits has allowed elucidation of their functions in specific tissues. The role of some subunits in human disease, however, has not been fully established, and their functions remain uncertain.

OBJECTIVE: We aimed to expand the range of neurodevelopmental disorders associated with mutations in TRAPP subunits by exome sequencing of consanguineous families.

METHODS: Linkage and homozygosity mapping and candidate gene analysis were used to identify homozygous mutations in families. Patient fibroblasts were used to study splicing defect and zebrafish to model the disease.

RESULTS: We identified six individuals from three unrelated families with a founder homozygous splice mutation in , encoding a core subunit of the complex TRAPP I. Patients manifested a neurodevelopmental disorder characterised by microcephaly, epilepsy and autistic features, and showed splicing defect. Zebrafish morphants replicated the human phenotype, displaying decreased head size and neuronal hyperexcitability, leading to a lower seizure threshold.

CONCLUSION: This study provides clinical and functional evidence of the role of in brain development and function.

}, keywords = {Animals, Autistic Disorder, Epilepsy, Founder Effect, Genetic Association Studies, Homozygote, Humans, Microcephaly, Mutation, Neurodevelopmental Disorders, Phenotype, Vesicular Transport Proteins, Zebrafish}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2017-104627}, author = {Marin-Valencia, Isaac and Novarino, Gaia and Johansen, Anide and Rosti, Basak and Issa, Mahmoud Y and Musaev, Damir and Bhat, Gifty and Scott, Eric and Silhavy, Jennifer L and Stanley, Valentina and Rosti, Rasim O and Gleeson, Jeremy W and Imam, Farhad B and Zaki, Maha S and Gleeson, Joseph G} } @article {514, title = {Loss of Protocadherin-12 Leads to Diencephalic-Mesencephalic Junction Dysplasia Syndrome.}, journal = {Ann Neurol}, volume = {84}, year = {2018}, month = {2018 Nov}, pages = {638-647}, abstract = {

OBJECTIVE: To identify causes of the autosomal-recessive malformation, diencephalic-mesencephalic junction dysplasia (DMJD) syndrome.

METHODS: Eight families with DMJD were studied by whole-exome or targeted sequencing, with detailed clinical and radiological characterization. Patient-derived induced pluripotent stem cells were derived into neural precursor and endothelial cells to study gene expression.

RESULTS: All patients showed biallelic mutations in the nonclustered protocadherin-12 (PCDH12) gene. The characteristic clinical presentation included progressive microcephaly, craniofacial dysmorphism, psychomotor disability, epilepsy, and axial hypotonia with variable appendicular spasticity. Brain imaging showed brainstem malformations and with frequent thinned corpus callosum with punctate brain calcifications, reflecting expression of PCDH12 in neural and endothelial cells. These cells showed lack of PCDH12 expression and impaired neurite outgrowth.

INTERPRETATION: DMJD patients have biallelic mutations in PCDH12 and lack of protein expression. These patients present with characteristic microcephaly and abnormalities of white matter tracts. Such pathogenic variants predict a poor outcome as a result of brainstem malformation and evidence of white matter tract defects, and should be added to the phenotypic spectrum associated with PCDH12-related conditions. Ann Neurol 2018;84:646-655.

}, issn = {1531-8249}, doi = {10.1002/ana.25327}, author = {Guemez-Gamboa, Alicia and {\c C}a{\u g}layan, Ahmet Okay and Stanley, Valentina and Gregor, Anne and Zaki, Maha S and Saleem, Sahar N and Musaev, Damir and McEvoy-Venneri, Jennifer and Belandres, Denice and Akizu, Naiara and Silhavy, Jennifer L and Schroth, Jana and Rosti, Rasim Ozgur and Copeland, Brett and Lewis, Steven M and Fang, Rebecca and Issa, Mahmoud Y and Per, H{\"u}seyin and G{\"u}m{\"u}{\c s}, Hakan and Bayram, Ayse Kacar and Kumanda{\c s}, Sefer and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Erson-Omay, Emine Z and Yasuno, Katsuhito and Bilguvar, Kaya and Heimer, Gali and Pillar, Nir and Shomron, Noam and Weissglas-Volkov, Daphna and Porat, Yuval and Einhorn, Yaron and Gabriel, Stacey and Ben-Zeev, Bruria and G{\"u}nel, Murat and Gleeson, Joseph G} } @article {560, title = {Loss of tubulin deglutamylase CCP1 causes infantile-onset neurodegeneration.}, journal = {EMBO J}, volume = {37}, year = {2018}, month = {2018 Dec 03}, abstract = {

A set of glutamylases and deglutamylases controls levels of tubulin polyglutamylation, a prominent post-translational modification of neuronal microtubules. Defective tubulin polyglutamylation was first linked to neurodegeneration in the () mouse, which lacks deglutamylase CCP1, displays massive cerebellar atrophy, and accumulates abnormally glutamylated tubulin in degenerating neurons. We found biallelic rare and damaging variants in the gene encoding CCP1 in 13 individuals with infantile-onset neurodegeneration and confirmed the absence of functional CCP1 along with dysregulated tubulin polyglutamylation. The human disease mainly affected the cerebellum, spinal motor neurons, and peripheral nerves. We also demonstrate previously unrecognized peripheral nerve and spinal motor neuron degeneration in mice, which thus recapitulated key features of the human disease. Our findings link human neurodegeneration to tubulin polyglutamylation, entailing this post-translational modification as a potential target for drug development for neurodegenerative disorders.

}, issn = {1460-2075}, doi = {10.15252/embj.2018100540}, author = {Shashi, Vandana and Magiera, Maria M and Klein, Dennis and Zaki, Maha and Schoch, Kelly and Rudnik-Sch{\"o}neborn, Sabine and Norman, Andrew and Lopes Abath Neto, Osorio and Dusl, Marina and Yuan, Xidi and Bartesaghi, Luca and De Marco, Patrizia and Alfares, Ahmed A and Marom, Ronit and Arold, Stefan T and Guzm{\'a}n-Vega, Francisco J and Pena, Loren Dm and Smith, Edward C and Steinlin, Maja and Babiker, Mohamed Oe and Mohassel, Payam and Foley, A Reghan and Donkervoort, Sandra and Kaur, Rupleen and Ghosh, Partha S and Stanley, Valentina and Musaev, Damir and Nava, Caroline and Mignot, Cyril and Keren, Boris and Scala, Marcello and Tassano, Elisa and Picco, Paolo and Doneda, Paola and Fiorillo, Chiara and Issa, Mahmoud Y and Alassiri, Ali and Alahmad, Ahmed and Gerard, Amanda and Liu, Pengfei and Yang, Yaping and Ertl-Wagner, Birgit and Kranz, Peter G and Wentzensen, Ingrid M and Stucka, Rolf and Stong, Nicholas and Allen, Andrew S and Goldstein, David B and Schoser, Benedikt and R{\"o}sler, Kai M and Alfadhel, Majid and Capra, Valeria and Chrast, Roman and Strom, Tim M and Kamsteeg, Erik-Jan and B{\"o}nnemann, Carsten G and Gleeson, Joseph G and Martini, Rudolf and Janke, Carsten and Senderek, Jan} } @article {488, title = {Mutations in LNPK, Encoding the Endoplasmic Reticulum Junction Stabilizer Lunapark, Cause a Recessive Neurodevelopmental Syndrome.}, journal = {Am J Hum Genet}, volume = {103}, year = {2018}, month = {2018 08 02}, pages = {296-304}, abstract = {

The dynamic shape of the endoplasmic reticulum (ER) is a reflection of its wide variety of critical cell biological functions. Consequently, perturbation of ER-shaping proteins can cause a range of human phenotypes. Here, we describe three affected children (from two consanguineous families) who carry homozygous loss-of-function mutations in LNPK (previously known as KIAA1715); this gene encodes lunapark, which is proposed to serve as a curvature-stabilizing protein within tubular three-way junctions of the ER. All individuals presented with severe psychomotor delay, intellectual disability, hypotonia, epilepsy, and corpus callosum hypoplasia, and two of three showed mild cerebellar hypoplasia and atrophy. Consistent with a proposed role in neurodevelopmental disease, LNPK was expressed during brain development in humans and mice and was present in neurite-like processes in differentiating human neural progenitor cells. Affected cells showed the absence of full-length lunapark, aberrant ER structures, and increased luminal mass density. Together, our results implicate the ER junction stabilizer lunapark in establishing the corpus callosum.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.06.011}, author = {Breuss, Martin W and Nguyen, An and Song, Qiong and Nguyen, Thai and Stanley, Valentina and James, Kiely N and Musaev, Damir and Chai, Guoliang and Wirth, Sara A and Anzenberg, Paula and George, Renee D and Johansen, Anide and Ali, Shaila and Zia-Ur-Rehman, Muhammad and Sultan, Tipu and Zaki, Maha S and Gleeson, Joseph G} } @article {382, title = {Homozygous Mutations in TBC1D23 Lead to a Non-degenerative Form of Pontocerebellar Hypoplasia.}, journal = {Am J Hum Genet}, volume = {101}, year = {2017}, month = {2017 Sep 07}, pages = {441-450}, abstract = {

Pontocerebellar hypoplasia (PCH) represents a group of recessive developmental disorders characterized by impaired growth of the pons and cerebellum, which frequently follows a degenerative course. Currently, there are 10 partially overlapping clinical subtypes and 13 genes known mutated in PCH. Here, we report biallelic TBC1D23 mutations in six individuals from four unrelated families manifesting a non-degenerative form of PCH. In addition to reduced volume of pons and cerebellum, affected individuals had microcephaly, psychomotor delay, and ataxia. In zebrafish, tbc1d23 morphants replicated the human phenotype showing hindbrain volume loss. TBC1D23 localized at the trans-Golgi and was regulated by the small GTPases Arl1 and Arl8, suggesting a role in trans-Golgi membrane trafficking. Altogether, this study provides a causative link between TBC1D23 mutations and PCH and suggests a less severe clinical course than other PCH subtypes.

}, keywords = {Adolescent, Animals, Cerebellar Diseases, Child, Child, Preschool, Female, GTPase-Activating Proteins, HeLa Cells, Homozygote, Humans, Male, Microcephaly, Mutation, Pedigree, Phenotype, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2017.07.015}, author = {Marin-Valencia, Isaac and Gerondopoulos, Andreas and Zaki, Maha S and Ben-Omran, Tawfeg and Almureikhi, Mariam and Demir, Ercan and Guemez-Gamboa, Alicia and Gregor, Anne and Issa, Mahmoud Y and Appelhof, Bart and Roosing, Susanne and Musaev, Damir and Rosti, Basak and Wirth, Sara and Stanley, Valentina and Baas, Frank and Barr, Francis A and Gleeson, Joseph G} }