@article {998, title = {CSNK2B: A broad spectrum of neurodevelopmental disability and epilepsy severity.}, journal = {Epilepsia}, year = {2021}, month = {2021 May 26}, abstract = {

CSNK2B has recently been implicated as a disease gene for neurodevelopmental disability (NDD) and epilepsy. Information about developmental outcomes has been limited by the young age and short follow-up for many of the previously reported cases, and further delineation of the spectrum of associated phenotypes is needed. We present 25 new patients with variants in CSNK2B and refine the associated NDD and epilepsy phenotypes. CSNK2B variants were identified by research or clinical exome sequencing, and investigators from different centers were connected via GeneMatcher. Most individuals had developmental delay and generalized epilepsy with onset in the first 2 years. However, we found a broad spectrum of phenotypic severity, ranging from early normal development with pharmacoresponsive seizures to profound intellectual disability with intractable epilepsy and recurrent refractory status epilepticus. These findings suggest that CSNK2B should be considered in the diagnostic evaluation of patients with a broad range of NDD with treatable or intractable seizures.

}, issn = {1528-1167}, doi = {10.1111/epi.16931}, author = {Ernst, Michelle E and Baugh, Evan H and Thomas, Amanda and Bier, Louise and Lippa, Natalie and Stong, Nicholas and Mulhern, Maureen S and Kushary, Sulagna and Akman, Cigdem I and Heinzen, Erin L and Yeh, Raymond and Bi, Weimin and Hanchard, Neil A and Burrage, Lindsay C and Leduc, Magalie S and Chong, Josephine S C and Bend, Renee and Lyons, Michael J and Lee, Jennifer A and Suwannarat, Pim and Brilstra, Eva and Simon, Marleen and Koopmans, Marije and van Binsbergen, Ellen and Groepper, Daniel and Fleischer, Julie and Nava, Caroline and Keren, Boris and Mignot, Cyril and Mathieu, Sophie and Mancini, Grazia M S and Madan-Khetarpal, Suneeta and Infante, Elena M and Bluvstein, Judith and Seeley, Andrea and Bachman, Kristine and Klee, Eric W and Schultz-Rogers, Laura E and Hasadsri, Linda and Barnett, Sarah and Ellingson, Marissa S and Ferber, Matthew J and Narayanan, Vinodh and Ramsey, Keri and Rauch, Anita and Joset, Pascal and Steindl, Katharina and Sheehan, Theodore and Poduri, Annapurna and Vasquez, Alejandra and Ruivenkamp, Claudia and White, Susan M and Pais, Lynn and Monaghan, Kristin G and Goldstein, David B and Sands, Tristan T and Aggarwal, Vimla} } @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 {558, title = {MACF1 Mutations Encoding Highly Conserved Zinc-Binding Residues of the GAR Domain Cause Defects in Neuronal Migration and Axon Guidance.}, journal = {Am J Hum Genet}, volume = {103}, year = {2018}, month = {2018 12 06}, pages = {1009-1021}, abstract = {

To date, mutations in 15 actin- or microtubule-associated genes have been associated with the cortical malformation lissencephaly and variable brainstem hypoplasia. During a multicenter review, we recognized a rare lissencephaly variant with a complex brainstem malformation in three unrelated children. We searched our large brain-malformation databases and found another five children with this malformation (as well as one with a less severe variant), analyzed available whole-exome or -genome sequencing data, and tested ciliogenesis in two affected individuals. The brain malformation comprised posterior predominant lissencephaly and midline crossing defects consisting of absent anterior commissure and a striking W-shaped brainstem malformation caused by small or absent pontine crossing fibers. We discovered heterozygous de novo missense variants or an in-frame deletion involving highly conserved zinc-binding residues within the GAR domain of MACF1 in the first eight subjects. We studied cilium formation and found a higher proportion of mutant cells with short cilia than of control cells with short cilia. A ninth child had similar lissencephaly but~only subtle brainstem dysplasia associated with a heterozygous de novo missense variant in the spectrin repeat domain of MACF1. Thus, we report variants of the microtubule-binding GAR domain of MACF1 as the cause of a distinctive and most likely pathognomonic brain malformation. A~gain-of-function or dominant-negative mechanism appears likely given that many heterozygous mutations leading to protein truncation are included in the ExAC Browser. However, three de novo variants in MACF1 have been observed in large schizophrenia cohorts.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.10.019}, author = {Dobyns, William B and Aldinger, Kimberly A and Ishak, Gisele E and Mirzaa, Ghayda M and Timms, Andrew E and Grout, Megan E and Dremmen, Marjolein H G and Schot, Rachel and Vandervore, Laura and van Slegtenhorst, Marjon A and Wilke, Martina and Kasteleijn, Esmee and Lee, Arthur S and Barry, Brenda J and Chao, Katherine R and Szcza{\l}uba, Krzysztof and Kobori, Joyce and Hanson-Kahn, Andrea and Bernstein, Jonathan A and Carr, Lucinda and D{\textquoteright}Arco, Felice and Miyana, Kaori and Okazaki, Tetsuya and Saito, Yoshiaki and Sasaki, Masayuki and Das, Soma and Wheeler, Marsha M and Bamshad, Michael J and Nickerson, Deborah A and Engle, Elizabeth C and Verheijen, Frans W and Doherty, Dan and Mancini, Grazia M S} } @article {610, title = {SYT1-associated neurodevelopmental disorder: a case series.}, journal = {Brain}, volume = {141}, year = {2018}, month = {2018 Sep 01}, pages = {2576-2591}, abstract = {

Synaptotagmin 1 (SYT1) is a critical mediator of fast, synchronous, calcium-dependent neurotransmitter release and also modulates synaptic vesicle endocytosis. This paper describes 11 patients with de novo heterozygous missense mutations in SYT1. All mutations alter highly conserved residues, and cluster in two regions of the SYT1 C2B domain at positions Met303 (M303K), Asp304 (D304G), Asp366 (D366E), Ile368 (I368T) and Asn371 (N371K). Phenotypic features include infantile hypotonia, congenital ophthalmic abnormalities, childhood-onset hyperkinetic movement disorders, motor stereotypies, and developmental delay varying in severity from moderate to profound. Behavioural characteristics include sleep disturbance and episodic agitation. Absence of epileptic seizures and normal orbitofrontal head circumference are important negative features. Structural MRI is unremarkable but EEG disturbance is universal, characterized by intermittent low frequency high amplitude oscillations. The functional impact of these five de novo SYT1 mutations has been assessed by expressing rat SYT1 protein containing the equivalent human variants in wild-type mouse primary hippocampal cultures. All mutant forms of SYT1 were expressed at levels approximately equal to endogenous wild-type protein, and correctly localized to nerve terminals at rest, except for SYT1M303K, which was expressed at a lower level and failed to localize at nerve terminals. Following stimulation, SYT1I368T and SYT1N371K relocalized to nerve terminals at least as efficiently as wild-type SYT1. However, SYT1D304G and SYT1D366E failed to relocalize to nerve terminals following stimulation, indicative of impairments in endocytic retrieval and trafficking of SYT1. In addition, the presence of SYT1 variants at nerve terminals induced a slowing of exocytic rate following sustained action potential stimulation. The extent of disturbance to synaptic vesicle kinetics is mirrored by the severity of the affected individuals{\textquoteright} phenotypes, suggesting that the efficiency of SYT1-mediated neurotransmitter release is critical to cognitive development. In summary, de novo dominant SYT1 missense mutations are associated with a recognizable neurodevelopmental syndrome, and further cases can now be diagnosed based on clinical features, electrophysiological signature and mutation characteristics. Variation in phenotype severity may reflect mutation-specific impact on the diverse physiological functions of SYT1.

}, issn = {1460-2156}, doi = {10.1093/brain/awy209}, author = {Baker, Kate and Gordon, Sarah L and Melland, Holly and Bumbak, Fabian and Scott, Daniel J and Jiang, Tess J and Owen, David and Turner, Bradley J and Boyd, Stewart G and Rossi, Mari and Al-Raqad, Mohammed and Elpeleg, Orly and Peck, Dawn and Mancini, Grazia M S and Wilke, Martina and Zollino, Marcella and Marangi, Giuseppe and Weigand, Heike and Borggraefe, Ingo and Haack, Tobias and Stark, Zornitza and Sadedin, Simon and Tan, Tiong Yang and Jiang, Yunyun and Gibbs, Richard A and Ellingwood, Sara and Amaral, Michelle and Kelley, Whitley and Kurian, Manju A and Cousin, Michael A and Raymond, F Lucy} } @article {464, title = {Truncating Variants in NAA15 Are Associated with Variable Levels of Intellectual Disability, Autism Spectrum Disorder, and Congenital Anomalies.}, journal = {Am J Hum Genet}, volume = {102}, year = {2018}, month = {2018 05 03}, pages = {985-994}, abstract = {

N-alpha-acetylation is a common co-translational protein modification that is essential for normal cell function in humans. We previously identified the genetic basis of an X-linked infantile lethal Mendelian disorder involving a c.109T>C (p.Ser37Pro) missense variant in NAA10, which encodes the catalytic subunit of the N-terminal acetyltransferase A (NatA) complex. The auxiliary subunit of the NatA complex, NAA15, is the dimeric binding partner for NAA10. Through a genotype-first approach with whole-exome or genome sequencing (WES/WGS) and targeted sequencing analysis, we identified and phenotypically characterized 38 individuals from 33 unrelated families with 25 different de novo or inherited, dominantly acting likely gene disrupting (LGD) variants in NAA15. Clinical features of affected individuals with LGD variants in NAA15 include variable levels of intellectual disability, delayed speech and motor milestones, and autism spectrum disorder. Additionally, mild craniofacial dysmorphology, congenital cardiac anomalies, and seizures are present in some subjects. RNA analysis in cell lines from two individuals showed degradation of the transcripts with LGD variants, probably as a result of nonsense-mediated decay. Functional assays in yeast confirmed a deleterious effect for two of the LGD variants in NAA15. Further supporting a mechanism of haploinsufficiency, individuals with copy-number variant (CNV) deletions involving NAA15 and surrounding genes can present with mild intellectual disability, mild dysmorphic features, motor delays, and decreased growth. We propose that defects in NatA-mediated N-terminal acetylation (NTA) lead to variable levels of neurodevelopmental disorders in humans, supporting the importance of the NatA complex in normal human development.

}, keywords = {Abnormalities, Multiple, Adolescent, Adult, Autism Spectrum Disorder, Cell Line, Child, Exons, Female, Gene Expression Regulation, Genetic Predisposition to Disease, Genetic Variation, Humans, Intellectual Disability, Male, Middle Aged, Mutation, N-Terminal Acetyltransferase A, N-Terminal Acetyltransferase E, Pedigree, Phenotype, RNA, Messenger, Saccharomyces cerevisiae}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.03.004}, author = {Cheng, Hanyin and Dharmadhikari, Avinash V and Varland, Sylvia and Ma, Ning and Domingo, Deepti and Kleyner, Robert and Rope, Alan F and Yoon, Margaret and Stray-Pedersen, Asbj{\o}rg and Posey, Jennifer E and Crews, Sarah R and Eldomery, Mohammad K and Akdemir, Zeynep Coban and Lewis, Andrea M and Sutton, Vernon R and Rosenfeld, Jill A and Conboy, Erin and Agre, Katherine and Xia, Fan and Walkiewicz, Magdalena and Longoni, Mauro and High, Frances A and van Slegtenhorst, Marjon A and Mancini, Grazia M S and Finnila, Candice R and van Haeringen, Arie and den Hollander, Nicolette and Ruivenkamp, Claudia and Naidu, Sakkubai and Mahida, Sonal and Palmer, Elizabeth E and Murray, Lucinda and Lim, Derek and Jayakar, Parul and Parker, Michael J and Giusto, Stefania and Stracuzzi, Emanuela and Romano, Corrado and Beighley, Jennifer S and Bernier, Raphael A and K{\"u}ry, S{\'e}bastien and Nizon, Mathilde and Corbett, Mark A and Shaw, Marie and Gardner, Alison and Barnett, Christopher and Armstrong, Ruth and Kassahn, Karin S and Van Dijck, Anke and Vandeweyer, Geert and Kleefstra, Tjitske and Schieving, Jolanda and Jongmans, Marjolijn J and de Vries, Bert B A and Pfundt, Rolph and Kerr, Bronwyn and Rojas, Samantha K and Boycott, Kym M and Person, Richard and Willaert, Rebecca and Eichler, Evan E and Kooy, R Frank and Yang, Yaping and Wu, Joseph C and Lupski, James R and Arnesen, Thomas and Cooper, Gregory M and Chung, Wendy K and Gecz, Jozef and Stessman, Holly A F and Meng, Linyan and Lyon, Gholson J} }