@article {886, title = {Community-based recruitment and exome sequencing indicates high diagnostic yield in adults with intellectual disability.}, journal = {Mol Genet Genomic Med}, volume = {8}, year = {2020}, month = {2020 10}, pages = {e1439}, abstract = {

BACKGROUND: Establishing a genetic diagnosis for individuals with intellectual disability (ID) benefits patients and their families as it may inform the prognosis, lead to appropriate therapy, and facilitate access to medical and supportive services. Exome sequencing has been successfully applied in a diagnostic setting, but most clinical exome referrals are pediatric patients, with many adults with ID lacking a comprehensive genetic evaluation.

METHODS: Our unique recruitment strategy involved partnering with service and education providers for individuals with ID. We performed exome sequencing and analysis, and clinical variant interpretation for each recruited family.

RESULTS: All five families enrolled in the study opted-in for the return of genetic results. In three out of five families exome sequencing analysis identified pathogenic or likely pathogenic variants in KANSL1, TUSC3, and MED13L genes. Families discussed the results and any potential medical follow-up in an appointment with a board certified clinical geneticist.

CONCLUSION: Our study suggests high yield of exome sequencing as a diagnostic tool in adult patients with ID who have not undergone comprehensive sequencing-based genetic testing. Research studies including an option of return of results through a genetic clinic could help minimize the disparity in exome diagnostic testing between pediatric and adult patients with ID.

}, keywords = {Adult, Female, Genetic Testing, Humans, Independent Living, Intellectual Disability, Male, Mediator Complex, Membrane Proteins, Nuclear Proteins, Patient Selection, Sensitivity and Specificity, Tumor Suppressor Proteins, Whole Exome Sequencing}, issn = {2324-9269}, doi = {10.1002/mgg3.1439}, author = {Sabo, Aniko and Murdock, David and Dugan, Shannon and Meng, Qingchang and Gingras, Marie-Claude and Hu, Jianhong and Muzny, Donna and Gibbs, Richard} } @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 {794, title = {Mutations disrupting neuritogenesis genes confer risk for cerebral palsy.}, journal = {Nat Genet}, volume = {52}, year = {2020}, month = {2020 10}, pages = {1046-1056}, abstract = {

In addition to commonly associated environmental factors, genomic factors may cause cerebral palsy. We performed whole-exome sequencing of 250 parent-offspring trios, and observed enrichment of damaging de novo mutations in cerebral palsy cases. Eight genes had multiple damaging de novo mutations; of these, two (TUBA1A and CTNNB1) met genome-wide significance. We identified two novel monogenic etiologies, FBXO31 and RHOB, and showed that the RHOB mutation enhances active-state Rho effector binding while the FBXO31 mutation diminishes cyclin D levels. Candidate cerebral palsy risk genes overlapped with neurodevelopmental disorder genes. Network analyses identified enrichment of Rho GTPase, extracellular matrix, focal adhesion and cytoskeleton pathways. Cerebral palsy risk genes in enriched pathways were shown to regulate neuromotor function in a Drosophila reverse genetics screen. We estimate that 14\% of cases could be attributed to an excess of damaging de novo or recessive variants. These findings provide evidence for genetically mediated dysregulation of early neuronal connectivity in cerebral palsy.

}, keywords = {Animals, beta Catenin, Cerebral Palsy, Cyclin D, Cytoskeleton, Drosophila, Exome, Extracellular Matrix, F-Box Proteins, Female, Focal Adhesions, Genetic Predisposition to Disease, Genome, Human, Humans, Male, Mutation, Neurites, rhoB GTP-Binding Protein, Risk Factors, Sequence Analysis, DNA, Signal Transduction, Tubulin, Tumor Suppressor Proteins, Whole Exome Sequencing}, issn = {1546-1718}, doi = {10.1038/s41588-020-0695-1}, author = {Jin, Sheng Chih and Lewis, Sara A and Bakhtiari, Somayeh and Zeng, Xue and Sierant, Michael C and Shetty, Sheetal and Nordlie, Sandra M and Elie, Aureliane and Corbett, Mark A and Norton, Bethany Y and van Eyk, Clare L and Haider, Shozeb and Guida, Brandon S and Magee, Helen and Liu, James and Pastore, Stephen and Vincent, John B and Brunstrom-Hernandez, Janice and Papavasileiou, Antigone and Fahey, Michael C and Berry, Jesia G and Harper, Kelly and Zhou, Chongchen and Zhang, Junhui and Li, Boyang and Zhao, Hongyu and Heim, Jennifer and Webber, Dani L and Frank, MAHlia S B and Xia, Lei and Xu, Yiran and Zhu, Dengna and Zhang, Bohao and Sheth, Amar H and Knight, James R and Castaldi, Christopher and Tikhonova, Irina R and L{\'o}pez-Gir{\'a}ldez, Francesc and Keren, Boris and Whalen, Sandra and Buratti, Julien and Doummar, Diane and Cho, Megan and Retterer, Kyle and Millan, Francisca and Wang, Yangong and Waugh, Jeff L and Rodan, Lance and Cohen, Julie S and Fatemi, Ali and Lin, Angela E and Phillips, John P and Feyma, Timothy and MacLennan, Suzanna C and Vaughan, Spencer and Crompton, Kylie E and Reid, Susan M and Reddihough, Dinah S and Shang, Qing and Gao, Chao and Novak, Iona and Badawi, Nadia and Wilson, Yana A and McIntyre, Sarah J and Mane, Shrikant M and Wang, Xiaoyang and Amor, David J and Zarnescu, Daniela C and Lu, Qiongshi and Xing, Qinghe and Zhu, Changlian and Bilguvar, Kaya and Padilla-Lopez, Sergio and Lifton, Richard P and Gecz, Jozef and MacLennan, Alastair H and Kruer, Michael C} } @article {49, title = {Ataxia-Pancytopenia Syndrome Is Caused by Missense Mutations in SAMD9L.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Jun 02}, pages = {1146-1158}, abstract = {

Ataxia-pancytopenia (AP) syndrome is characterized by cerebellar ataxia, variable hematologic cytopenias, and predisposition to marrow failure and myeloid leukemia, sometimes associated with monosomy 7. Here, in the four-generation family UW-AP, linkage analysis revealed four regions that provided the maximal LOD scores possible, one of which was in a commonly microdeleted chromosome 7q region. Exome sequencing identified a missense mutation (c.2640C>A, p.His880Gln) in the sterile alpha motif domain containing 9-like gene (SAMD9L) that completely cosegregated with disease. By targeted sequencing of SAMD9L, we subsequently identified a different missense mutation (c.3587G>C, p.Cys1196Ser) in affected members of the first described family with AP syndrome, Li-AP. Neither variant is reported in the public databases, both affect highly conserved amino acid residues, and both are predicted to be damaging. With time in culture, lymphoblastic cell lines (LCLs) from two affected individuals in family UW-AP exhibited copy-neutral loss of heterozygosity for large portions of the long arm of chromosome 7, resulting in retention of only the wild-type SAMD9L allele. Newly established LCLs from both individuals demonstrated the same phenomenon. In addition, targeted capture and sequencing of SAMD9L in uncultured blood DNA from both individuals showed bias toward the wild-type allele. These observations indicate in~vivo hematopoietic mosaicism. The hematopoietic cytopenias that characterize AP syndrome and the selective advantage for clones that have lost the mutant allele support the postulated role of SAMD9L in the regulation of cell proliferation. Furthermore, we show that AP syndrome is distinct from the dyskeratoses congenita telomeropathies, with which it shares some clinical characteristics.

}, keywords = {Adolescent, Adult, Cerebellar Ataxia, Child, Chromosome Aberrations, Chromosomes, Human, Pair 7, Exome, Female, Genetic Linkage, Genotype, High-Throughput Nucleotide Sequencing, Humans, Intracellular Signaling Peptides and Proteins, Loss of Heterozygosity, Male, Middle Aged, Mutation, Missense, Pancytopenia, Pedigree, Proteins, Tumor Suppressor Proteins, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.04.009}, author = {Chen, Dong-Hui and Below, Jennifer E and Shimamura, Akiko and Keel, Sioban B and Matsushita, Mark and Wolff, John and Sul, Youngmee and Bonkowski, Emily and Castella, Maria and Taniguchi, Toshiyasu and Nickerson, Deborah and Papayannopoulou, Thalia and Bird, Thomas D and Raskind, Wendy H} } @article {35, title = {IFT52 mutations destabilize anterograde complex assembly, disrupt ciliogenesis and result in short rib polydactyly syndrome.}, journal = {Hum Mol Genet}, volume = {25}, year = {2016}, month = {2016 Sep 15}, pages = {4012-4020}, abstract = {

The short-rib polydactyly syndromes (SRPS) encompass a radiographically and genetically heterogeneous group of skeletal ciliopathies that are characterized by a long narrow chest, short extremities, and variable occurrence of polydactyly. Radiographic abnormalities include undermineralization of the calvarium, shortened and bowed appendicular bones, trident shaped acetabula and polydactyly. In a case of SRPS we identified compound heterozygosity for mutations in IFT52, which encodes a component of the anterograde intraflagellar transport complex. The IFT52 mutant cells synthesized a significantly reduced amount of IFT52 protein, leading to reduced synthesis of IFT74, IFT81, IFT88 and ARL13B, other key anterograde complex members. Ciliogenesis was also disrupted in the mutant cells, with a 60\% reduction in the presence of cilia on mutant cells and loss of cilia length regulation for the cells with cilia. These data demonstrate that IFT52 is essential for anterograde complex integrity and for the biosynthesis and maintenance of cilia. The data identify a new locus for SRPS and show that IFT52 mutations result in a ciliopathy with primary effects on the skeleton.

}, keywords = {Carrier Proteins, Cilia, Ciliopathies, Cytoskeletal Proteins, Flagella, Humans, Intracellular Signaling Peptides and Proteins, Multiprotein Complexes, Muscle Proteins, Mutation, Short Rib-Polydactyly Syndrome, Skeleton, Tumor Suppressor Proteins}, issn = {1460-2083}, doi = {10.1093/hmg/ddw241}, author = {Zhang, Wenjuan and Taylor, S Paige and Nevarez, Lisette and Lachman, Ralph S and Nickerson, Deborah A and Bamshad, Michael and Krakow, Deborah and Cohn, Daniel H} } @article {161, title = {Inactivating mutations in MFSD2A, required for omega-3 fatty acid transport in brain, cause a lethal microcephaly syndrome.}, journal = {Nat Genet}, volume = {47}, year = {2015}, month = {2015 Jul}, pages = {809-13}, abstract = {

Docosahexanoic acid (DHA) is the most abundant omega-3 fatty acid in brain, and, although it is considered essential, deficiency has not been linked to disease. Despite the large mass of DHA in phospholipids, the brain does not synthesize it. DHA is imported across the blood-brain barrier (BBB) through the major facilitator superfamily domain-containing 2a (MFSD2A) protein. MFSD2A transports DHA as well as other fatty acids in the form of lysophosphatidylcholine (LPC). We identify two families displaying MFSD2A mutations in conserved residues. Affected individuals exhibited a lethal microcephaly syndrome linked to inadequate uptake of LPC lipids. The MFSD2A mutations impaired transport activity in a cell-based assay. Moreover, when expressed in mfsd2aa-morphant zebrafish, mutants failed to rescue microcephaly, BBB breakdown and lethality. Our results establish a link between transport of DHA and LPCs by MFSD2A and human brain growth and function, presenting the first evidence of monogenic disease related to transport of DHA in humans.

}, keywords = {Adolescent, Animals, Biological Transport, Blood-Brain Barrier, Brain, Case-Control Studies, Child, Child, Preschool, Consanguinity, Fatty Acids, Omega-3, Female, Genes, Lethal, Genetic Association Studies, HEK293 Cells, Humans, Infant, Male, Mice, Knockout, Microcephaly, Mutation, Missense, Syndrome, Tumor Suppressor Proteins, Zebrafish}, issn = {1546-1718}, doi = {10.1038/ng.3311}, author = {Guemez-Gamboa, Alicia and Nguyen, Long N and Yang, Hongbo and Zaki, Maha S and Kara, Majdi and Ben-Omran, Tawfeg and Akizu, Naiara and Rosti, Rasim Ozgur and Rosti, Basak and Scott, Eric and Schroth, Jana and Copeland, Brett and Vaux, Keith K and Cazenave-Gassiot, Amaury and Quek, Debra Q Y and Wong, Bernice H and Tan, Bryan C and Wenk, Markus R and G{\"u}nel, Murat and Gabriel, Stacey and Chi, Neil C and Silver, David L and Gleeson, Joseph G} }