@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 {786, title = {Further delineation of the clinical spectrum of KAT6B disorders and allelic series of pathogenic variants.}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 08}, pages = {1338-1347}, abstract = {

PURPOSE: Genitopatellar syndrome and Say-Barber-Biesecker-Young-Simpson syndrome are caused by variants in the KAT6B gene and are part of a broad clinical spectrum called KAT6B disorders, whose variable expressivity is increasingly being recognized.

METHODS: We herein present the phenotypes of 32 previously unreported individuals with a molecularly confirmed diagnosis of a KAT6B disorder, report 24 new pathogenic KAT6B variants, and review phenotypic information available on all published individuals with this condition. We also suggest a classification of clinical subtypes within the KAT6B disorder spectrum.

RESULTS: We demonstrate that cerebral anomalies, optic nerve hypoplasia, neurobehavioral difficulties, and distal limb anomalies other than long thumbs and great toes, such as polydactyly, are more frequently observed than initially reported. Intestinal malrotation and its serious consequences can be present in affected individuals. Additionally, we identified four children with Pierre Robin sequence, four individuals who had increased nuchal translucency/cystic hygroma prenatally, and two fetuses with severe renal anomalies leading to renal failure. We also report an individual in which a pathogenic variant was inherited from a mildly affected parent.

CONCLUSION: Our work provides a comprehensive review and expansion of the genotypic and phenotypic spectrum of KAT6B disorders that will assist clinicians in the assessment, counseling, and management of affected individuals.

}, keywords = {Blepharophimosis, Exons, Histone Acetyltransferases, Humans, Intellectual Disability, Mutation}, issn = {1530-0366}, doi = {10.1038/s41436-020-0811-8}, author = {Zhang, Li Xin and Lemire, Gabrielle and Gonzaga-Jauregui, Claudia and Molidperee, Sirinart and Galaz-Montoya, Carolina and Liu, David S and Verloes, Alain and Shillington, Amelle G and Izumi, Kosuke and Ritter, Alyssa L and Keena, Beth and Zackai, Elaine and Li, Dong and Bhoj, Elizabeth and Tarpinian, Jennifer M and Bedoukian, Emma and Kukolich, Mary K and Innes, A Micheil and Ediae, Grace U and Sawyer, Sarah L and Nair, Karippoth Mohandas and Soumya, Para Chottil and Subbaraman, Kinattinkara R and Probst, Frank J and Bassetti, Jennifer A and Sutton, Reid V and Gibbs, Richard A and Brown, Chester and Boone, Philip M and Holm, Ingrid A and Tartaglia, Marco and Ferrero, Giovanni Battista and Niceta, Marcello and Dentici, Maria Lisa and Radio, Francesca Clementina and Keren, Boris and Wells, Constance F and Coubes, Christine and Laquerri{\`e}re, Annie and Aziza, Jacqueline and Dubucs, Charlotte and Nampoothiri, Sheela and Mowat, David and Patel, Millan S and Bracho, Ana and Cammarata-Scalisi, Francisco and Gezdirici, Alper and Fern{\'a}ndez-Ja{\'e}n, Alberto and Hauser, Natalie and Zarate, Yuri A and Bosanko, Katherine A and Dieterich, Klaus and Carey, John C and Chong, Jessica X and Nickerson, Deborah A and Bamshad, Michael J and Lee, Brendan H and Yang, Xiang-Jiao and Lupski, James R and Campeau, Philippe M} } @article {770, title = {MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.}, journal = {Brain}, volume = {143}, year = {2020}, month = {2020 01 01}, pages = {55-68}, abstract = {

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3{\textquoteright} region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.

}, keywords = {Abnormalities, Multiple, Adolescent, Basilar Artery, Carotid Arteries, Cerebellar Vermis, Cerebellum, Child, Child, Preschool, Cohort Studies, Comparative Genomic Hybridization, Craniofacial Abnormalities, Female, Fibroblasts, Humans, Imaging, Three-Dimensional, Infant, Intellectual Disability, Language Development Disorders, Magnetic Resonance Imaging, Male, Middle Aged, Mutation, Nervous System Malformations, Nonsense Mediated mRNA Decay, Polymicrogyria, Real-Time Polymerase Chain Reaction, RNA-Seq, Syndrome, Tomography, X-Ray Computed, Trans-Activators, Tumor Suppressor Proteins, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1460-2156}, doi = {10.1093/brain/awz379}, author = {Mak, Christopher C Y and Doherty, Dan and Lin, Angela E and Vegas, Nancy and Cho, Megan T and Viot, G{\'e}raldine and Dimartino, Cl{\'e}mantine and Weisfeld-Adams, James D and Lessel, Davor and Joss, Shelagh and Li, Chumei and Gonzaga-Jauregui, Claudia and Zarate, Yuri A and Ehmke, Nadja and Horn, Denise and Troyer, Caitlin and Kant, Sarina G and Lee, Youngha and Ishak, Gisele E and Leung, Gordon and Barone Pritchard, Amanda and Yang, Sandra and Bend, Eric G and Filippini, Francesca and Roadhouse, Chelsea and Lebrun, Nicolas and Mehaffey, Michele G and Martin, Pierre-Marie and Apple, Benjamin and Millan, Francisca and Puk, Oliver and Hoffer, Mariette J V and Henderson, Lindsay B and McGowan, Ruth and Wentzensen, Ingrid M and Pei, Steven and Zahir, Farah R and Yu, Mullin and Gibson, William T and Seman, Ann and Steeves, Marcie and Murrell, Jill R and Luettgen, Sabine and Francisco, Elizabeth and Strom, Tim M and Amlie-Wolf, Louise and Kaindl, Angela M and Wilson, William G and Halbach, Sara and Basel-Salmon, Lina and Lev-El, Noa and Denecke, Jonas and Vissers, Lisenka E L M and Radtke, Kelly and Chelly, Jamel and Zackai, Elaine and Friedman, Jan M and Bamshad, Michael J and Nickerson, Deborah A and Reid, Russell R and Devriendt, Koenraad and Chae, Jong-Hee and Stolerman, Elliot and McDougall, Carey and Powis, Z{\"o}e and Bienvenu, Thierry and Tan, Tiong Y and Orenstein, Naama and Dobyns, William B and Shieh, Joseph T and Choi, Murim and Waggoner, Darrel and Gripp, Karen W and Parker, Michael J and Stoler, Joan and Lyonnet, Stanislas and Cormier-Daire, Val{\'e}rie and Viskochil, David and Hoffman, Trevor L and Amiel, Jeanne and Chung, Brian H Y and Gordon, Christopher T} } @article {589, title = {Missense Variants in the Histone Acetyltransferase Complex Component Gene TRRAP Cause Autism and Syndromic Intellectual Disability.}, journal = {Am J Hum Genet}, volume = {104}, year = {2019}, month = {2019 03 07}, pages = {530-541}, abstract = {

Acetylation of the lysine residues in histones and other DNA-binding proteins plays a major role in regulation of eukaryotic gene expression. This process is controlled by histone acetyltransferases (HATs/KATs) found in multiprotein complexes that are recruited to chromatin by the scaffolding subunit transformation/transcription domain-associated protein (TRRAP). TRRAP is evolutionarily conserved and is among the top five genes intolerant to missense variation. Through an international collaboration, 17 distinct de novo or apparently de novo variants were identified in TRRAP in 24 individuals. A strong genotype-phenotype correlation was observed with two distinct clinical spectra. The first is a complex, multi-systemic syndrome associated with various malformations of the brain, heart, kidneys, and genitourinary system and characterized by a wide range of intellectual functioning; a number of affected individuals have intellectual disability (ID) and markedly impaired basic life functions. Individuals with this phenotype had missense variants clustering around the c.3127G>A p.(Ala1043Thr) variant identified in five individuals. The second spectrum manifested with autism spectrum disorder (ASD) and/or ID and epilepsy. Facial dysmorphism was seen in both groups and included upslanted palpebral fissures, epicanthus, telecanthus, a wide nasal bridge and ridge, a broad and smooth philtrum, and a thin upper lip. RNA sequencing analysis of skin fibroblasts derived from affected individuals skin fibroblasts showed significant changes in the expression of several genes implicated in neuronal function and ion transport. Thus, we describe here the clinical spectrum associated with TRRAP pathogenic missense variants, and we suggest a genotype-phenotype correlation useful for clinical evaluation of the pathogenicity of the variants.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.01.010}, author = {Cogn{\'e}, Benjamin and Ehresmann, Sophie and Beauregard-Lacroix, Eliane and Rousseau, Justine and Besnard, Thomas and Garcia, Thomas and Petrovski, Slav{\'e} and Avni, Shiri and McWalter, Kirsty and Blackburn, Patrick R and Sanders, Stephan J and Uguen, K{\'e}vin and Harris, Jacqueline and Cohen, Julie S and Blyth, Moira and Lehman, Anna and Berg, Jonathan and Li, Mindy H and Kini, Usha and Joss, Shelagh and von der Lippe, Charlotte and Gordon, Christopher T and Humberson, Jennifer B and Robak, Laurie and Scott, Daryl A and Sutton, Vernon R and Skraban, Cara M and Johnston, Jennifer J and Poduri, Annapurna and Nordenskj{\"o}ld, Magnus and Shashi, Vandana and Gerkes, Erica H and Bongers, Ernie M H F and Gilissen, Christian and Zarate, Yuri A and Kvarnung, Malin and Lally, Kevin P and Kulch, Peggy A and Daniels, Brina and Hernandez-Garcia, Andres and Stong, Nicholas and McGaughran, Julie and Retterer, Kyle and Tveten, Kristian and Sullivan, Jennifer and Geisheker, Madeleine R and Stray-Pedersen, Asbjorg and Tarpinian, Jennifer M and Klee, Eric W and Sapp, Julie C and Zyskind, Jacob and Holla, {\O}ystein L and Bedoukian, Emma and Filippini, Francesca and Guimier, Anne and Picard, Arnaud and Busk, {\O}yvind L and Punetha, Jaya and Pfundt, Rolph and Lindstrand, Anna and Nordgren, Ann and Kalb, Fayth and Desai, Megha and Ebanks, Ashley Harmon and Jhangiani, Shalini N and Dewan, Tammie and Coban Akdemir, Zeynep H and Telegrafi, Aida and Zackai, Elaine H and Begtrup, Amber and Song, Xiaofei and Toutain, Annick and Wentzensen, Ingrid M and Odent, Sylvie and Bonneau, Dominique and Latypova, X{\'e}nia and Deb, Wallid and Redon, Sylvia and Bilan, Fr{\'e}d{\'e}ric and Legendre, Marine and Troyer, Caitlin and Whitlock, Kerri and Caluseriu, Oana and Murphree, Marine I and Pichurin, Pavel N and Agre, Katherine and Gavrilova, Ralitza and Rinne, Tuula and Park, Meredith and Shain, Catherine and Heinzen, Erin L and Xiao, Rui and Amiel, Jeanne and Lyonnet, Stanislas and Isidor, Bertrand and Biesecker, Leslie G and Lowenstein, Dan and Posey, Jennifer E and Denomm{\'e}-Pichon, Anne-Sophie and F{\'e}rec, Claude and Yang, Xiang-Jiao and Rosenfeld, Jill A and Gilbert-Dussardier, Brigitte and Audebert-Bellanger, S{\'e}verine and Redon, Richard and Stessman, Holly A F and Nellaker, Christoffer and Yang, Yaping and Lupski, James R and Goldstein, David B and Eichler, Evan E and Bolduc, Francois and B{\'e}zieau, St{\'e}phane and K{\"u}ry, S{\'e}bastien and Campeau, Philippe M} } @article {685, title = {Redefining the Etiologic Landscape of Cerebellar Malformations.}, journal = {Am J Hum Genet}, volume = {105}, year = {2019}, month = {2019 Sep 05}, pages = {606-615}, abstract = {

Cerebellar malformations are diverse congenital anomalies frequently associated with developmental disability. Although genetic and prenatal non-genetic causes have been described, no systematic analysis has been performed. Here, we present a large-exome sequencing study of Dandy-Walker malformation (DWM) and cerebellar hypoplasia (CBLH). We performed exome sequencing in 282 individuals from 100 families with DWM or CBLH, and we established a molecular diagnosis in 36 of 100 families, with a significantly higher yield for CBLH (51\%) than for DWM (16\%). The 41 variants impact 27 neurodevelopmental-disorder-associated genes, thus demonstrating that CBLH and DWM are often features of monogenic neurodevelopmental disorders. Though only seven monogenic causes (19\%) were identified in more than one individual, neuroimaging review of 131 additional individuals confirmed cerebellar abnormalities in 23 of 27 genetic disorders (85\%). Prenatal risk factors were frequently found among individuals without a genetic diagnosis (30 of 64 individuals [47\%]). Single-cell RNA sequencing of prenatal human cerebellar tissue revealed gene enrichment in neuronal and vascular cell types; this suggests that defective vasculogenesis may disrupt cerebellar development. Further, de novo gain-of-function variants in PDGFRB, a tyrosine kinase receptor essential for vascular progenitor signaling, were associated with CBLH, and this discovery links genetic and non-genetic etiologies. Our results suggest that genetic defects impact specific cerebellar cell types and implicate abnormal vascular development as a mechanism for cerebellar malformations. We also confirmed a major contribution for non-genetic prenatal factors in individuals with cerebellar abnormalities, substantially influencing diagnostic evaluation and counseling regarding recurrence risk and prognosis.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.07.019}, author = {Aldinger, Kimberly A and Timms, Andrew E and Thomson, Zachary and Mirzaa, Ghayda M and Bennett, James T and Rosenberg, Alexander B and Roco, Charles M and Hirano, Matthew and Abidi, Fatima and Haldipur, Parthiv and Cheng, Chi V and Collins, Sarah and Park, Kaylee and Zeiger, Jordan and Overmann, Lynne M and Alkuraya, Fowzan S and Biesecker, Leslie G and Braddock, Stephen R and Cathey, Sara and Cho, Megan T and Chung, Brian H Y and Everman, David B and Zarate, Yuri A and Jones, Julie R and Schwartz, Charles E and Goldstein, Amy and Hopkin, Robert J and Krantz, Ian D and Ladda, Roger L and Leppig, Kathleen A and McGillivray, Barbara C and Sell, Susan and Wusik, Katherine and Gleeson, Joseph G and Nickerson, Deborah A and Bamshad, Michael J and Gerrelli, Dianne and Lisgo, Steven N and Seelig, Georg and Ishak, Gisele E and Barkovich, A James and Curry, Cynthia J and Glass, Ian A and Millen, Kathleen J and Doherty, Dan and Dobyns, William B} }