@article {918, title = {De novo variants in SNAP25 cause an early-onset developmental and epileptic encephalopathy.}, journal = {Genet Med}, volume = {23}, year = {2021}, month = {2021 04}, pages = {653-660}, abstract = {

PURPOSE: This study aims to provide a comprehensive description of the phenotypic and genotypic spectrum of SNAP25 developmental and epileptic encephalopathy (SNAP25-DEE) by reviewing newly identified and previously reported individuals.

METHODS: Individuals harboring heterozygous missense or loss-of-function variants in SNAP25 were assembled through collaboration with international colleagues, matchmaking platforms, and literature review. For each individual, detailed phenotyping, classification, and structural modeling of the identified variant were performed.

RESULTS: The cohort comprises 23 individuals with pathogenic or likely pathogenic de novo variants in SNAP25. Intellectual disability and early-onset epilepsy were identified as the core symptoms of SNAP25-DEE, with recurrent findings of movement disorders, cerebral visual impairment, and brain atrophy. Structural modeling for all variants predicted possible functional defects concerning SNAP25 or impaired interaction with other components of the SNARE complex.

CONCLUSION: We provide a comprehensive description of SNAP25-DEE with intellectual disability and early-onset epilepsy mostly occurring before the age of two years. These core symptoms and additional recurrent phenotypes show an overlap to genes encoding other components or associated proteins of the SNARE complex such as STX1B, STXBP1, or VAMP2. Thus, these findings advance the concept of a group of neurodevelopmental disorders that may be termed "SNAREopathies."

}, keywords = {Brain Diseases, Child, Preschool, Epilepsy, Humans, Intellectual Disability, Neurodevelopmental Disorders, Phenotype, Synaptosomal-Associated Protein 25}, issn = {1530-0366}, doi = {10.1038/s41436-020-01020-w}, author = {Kl{\"o}ckner, Chiara and Sticht, Heinrich and Zacher, Pia and Popp, Bernt and Babcock, Holly E and Bakker, Dewi P and Barwick, Katy and Bonfert, Michaela V and B{\"o}nnemann, Carsten G and Brilstra, Eva H and Chung, Wendy K and Clarke, Angus J and Devine, Patrick and Donkervoort, Sandra and Fraser, Jamie L and Friedman, Jennifer and Gates, Alyssa and Ghoumid, Jamal and Hobson, Emma and Horvath, Gabriella and Keller-Ramey, Jennifer and Keren, Boris and Kurian, Manju A and Lee, Virgina and Leppig, Kathleen A and Lundgren, Johan and McDonald, Marie T and McLaughlin, Heather M and McTague, Amy and Mefford, Heather C and Mignot, Cyril and Mikati, Mohamad A and Nava, Caroline and Raymond, F Lucy and Sampson, Julian R and Sanchis-Juan, Alba and Shashi, Vandana and Shieh, Joseph T C and Shinawi, Marwan and Slavotinek, Anne and St{\"o}dberg, Tommy and Stong, Nicholas and Sullivan, Jennifer A and Taylor, Ashley C and Toler, Tomi L and van den Boogaard, Marie-Jos{\'e} and van der Crabben, Saskia N and van Gassen, Koen L I and van Jaarsveld, Richard H and Van Ziffle, Jessica and Wadley, Alexandrea F and Wagner, Matias and Wigby, Kristen and Wortmann, Saskia B and Zarate, Yuri A and M{\o}ller, Rikke S and Lemke, Johannes R and Platzer, Konrad} } @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 {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 {561, title = {Novel SPEG mutations in congenital myopathies: Genotype-phenotype correlations.}, journal = {Muscle Nerve}, volume = {59}, year = {2019}, month = {2019 03}, pages = {357-362}, abstract = {

INTRODUCTION: Centronuclear myopathies (CNMs) are a subtype of congenital myopathies (CMs) characterized by muscle weakness, predominant type 1 fibers, and increased central nuclei. SPEG (striated preferentially expressed protein kinase) mutations have recently been identified in 7 CM patients (6 with CNMs). We report 2 additional patients with SPEG mutations expanding the phenotype and evaluate genotype-phenotype correlations associated with SPEG mutations.

METHODS: Using whole exome/genome sequencing in CM families, we identified novel recessive SPEG mutations in 2 patients.

RESULTS: Patient 1, with severe muscle weakness requiring respiratory support, dilated cardiomyopathy, ophthalmoplegia, and findings of nonspecific CM on muscle biopsy carried a homozygous SPEG mutation (p.Val3062del). Patient 2, with milder muscle weakness, ophthalmoplegia, and CNM carried compound heterozygous mutations (p.Leu728Argfs*82) and (p.Val2997Glyfs*52).

CONCLUSIONS: The 2 patients add insight into genotype-phenotype correlations of SPEG-associated CMs. Clinicians should consider evaluating a CM patient for SPEG mutations even in the absence of CNM features. Muscle Nerve 59:357-362, 2019.

}, keywords = {Biopsy, Child, Child, Preschool, Consanguinity, Exome, Female, Genetic Association Studies, Humans, Infant, Male, Muscle Proteins, Muscle Weakness, Muscle, Skeletal, Mutation, Myopathies, Structural, Congenital, Protein-Serine-Threonine Kinases, Sequence Analysis}, issn = {1097-4598}, doi = {10.1002/mus.26378}, author = {Qualls, Anita E and Donkervoort, Sandra and Herkert, Johanna C and D{\textquoteright}Gama, Alissa M and Bharucha-Goebel, Diana and Collins, James and Chao, Katherine R and Foley, A Reghan and Schoots, Mirthe H and Jongbloed, Jan D H and B{\"o}nnemann, Carsten G and Agrawal, Pankaj B} } @article {490, title = {Variants in EXOSC9 Disrupt the RNA Exosome and Result in Cerebellar Atrophy with Spinal Motor Neuronopathy.}, journal = {Am J Hum Genet}, volume = {102}, year = {2018}, month = {2018 05 03}, pages = {858-873}, abstract = {

The exosome is a conserved multi-protein complex that is essential for correct RNA processing. Recessive variants in exosome components EXOSC3, EXOSC8, and RBM7 cause various constellations of pontocerebellar hypoplasia (PCH), spinal muscular atrophy (SMA), and central nervous system demyelination. Here, we report on four unrelated affected individuals with recessive variants in EXOSC9 and the effect of the variants on the function of the RNA exosome in~vitro in affected individuals{\textquoteright} fibroblasts and skeletal muscle and in~vivo in zebrafish. The clinical presentation was severe, early-onset, progressive SMA-like motor neuronopathy, cerebellar atrophy, and in one affected individual, congenital fractures of the long bones. Three affected individuals of different ethnicity carried the homozygous c.41T>C (p.Leu14Pro) variant, whereas one affected individual was compound heterozygous for c.41T>C (p.Leu14Pro) and c.481C>T (p.Arg161). We detected reduced EXOSC9 in fibroblasts and skeletal muscle and observed a reduction of the whole multi-subunit exosome complex on blue-native polyacrylamide gel electrophoresis. RNA sequencing of fibroblasts and skeletal muscle detected significant >2-fold changes in genes involved in neuronal development and cerebellar and motor neuron degeneration, demonstrating the widespread effect of the variants. Morpholino oligonucleotide knockdown and CRISPR/Cas9-mediated mutagenesis of exosc9 in zebrafish recapitulated aspects of the human phenotype, as they have in other zebrafish models of exosomal disease. Specifically, portions of the cerebellum and hindbrain were absent, and motor neurons failed to develop and migrate properly. In summary, we show that variants in EXOSC9 result in a neurological syndrome combining cerebellar atrophy and spinal motoneuronopathy, thus expanding the list of human exosomopathies.

}, keywords = {Amino Acid Sequence, Animals, Atrophy, Base Sequence, Cerebellum, Child, Preschool, Exosome Multienzyme Ribonuclease Complex, Exosomes, Female, Fibroblasts, Gene Knockdown Techniques, Genetic Variation, Haplotypes, Humans, Infant, Male, Motor Neurons, Muscle, Skeletal, Pedigree, RNA-Binding Proteins, Spinal Cord, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.03.011}, author = {Burns, David T and Donkervoort, Sandra and M{\"u}ller, Juliane S and Knierim, Ellen and Bharucha-Goebel, Diana and Faqeih, Eissa Ali and Bell, Stephanie K and AlFaifi, Abdullah Y and Monies, Dorota and Millan, Francisca and Retterer, Kyle and Dyack, Sarah and MacKay, Sara and Morales-Gonzalez, Susanne and Giunta, Michele and Munro, Benjamin and Hudson, Gavin and Scavina, Mena and Baker, Laura and Massini, Tara C and Lek, Monkol and Hu, Ying and Ezzo, Daniel and Alkuraya, Fowzan S and Kang, Peter B and Griffin, Helen and Foley, A Reghan and Schuelke, Markus and Horvath, Rita and B{\"o}nnemann, Carsten G} }