@article {149, title = {Germline mutation in : a heterogeneous, multi-systemic developmental disorder characterized by transcriptional dysregulation.}, journal = {HGG Adv}, volume = {2}, year = {2021}, month = {2021 Jan 14}, abstract = {

germline variation in was recently reported to associate with a neurodevelopmental disorder. We report twelve individuals harboring putatively pathogenic or inherited variants in , detail their phenotypes, and map all known variants to the domain structure of and crystal structure of RNA polymerase II. Affected individuals were ascertained from a local data lake, pediatric genetics clinic, and an online community of families of affected individuals. These include six affected by missense variants (including one previously reported individual), four clinical laboratory samples affected by missense variation with unknown inheritance-with yeast functional assays further supporting altered function-one affected by a in-frame deletion, and one affected by a C-terminal frameshift variant inherited from a largely asymptomatic mother. Recurrently observed phenotypes include ataxia, joint hypermobility, short stature, skin abnormalities, congenital cardiac abnormalities, immune system abnormalities, hip dysplasia, and short Achilles tendons. We report a significantly higher occurrence of epilepsy (8/12, 66.7\%) than previously reported (3/15, 20\%) (p value = 0.014196; chi-square test) and a lower occurrence of hypotonia (8/12, 66.7\%) than previously reported (14/15, 93.3\%) (p value = 0.076309). -related developmental disorders likely represent a spectrum of related, multi-systemic developmental disorders, driven by distinct mechanisms, converging at a single locus.

}, issn = {2666-2477}, doi = {10.1016/j.xhgg.2020.100014}, author = {Hansen, Adam W and Arora, Payal and Khayat, Michael M and Smith, Leah J and Lewis, Andrea M and Rossetti, Linda Z and Jayaseelan, Joy and Cristian, Ingrid and Haynes, Devon and DiTroia, Stephanie and Meeks, Naomi and Delgado, Mauricio R and Rosenfeld, Jill A and Pais, Lynn and White, Susan M and Meng, Qingchang and Pehlivan, Davut and Liu, Pengfei and Gingras, Marie-Claude and Wangler, Michael F and Muzny, Donna M and Lupski, James R and Kaplan, Craig D and Gibbs, Richard A} } @article {158, title = {Phenotypic and protein localization heterogeneity associated with AHDC1 pathogenic protein-truncating alleles in Xia-Gibbs syndrome.}, journal = {Hum Mutat}, volume = {42}, year = {2021}, month = {2021 May}, pages = {577-591}, abstract = {

Xia-Gibbs syndrome (XGS) is a rare Mendelian disease typically caused by de novo stop-gain or frameshift mutations in the AT-hook DNA binding motif containing 1 (AHDC1) gene. Patients usually present in early infancy with hypotonia and developmental delay and later exhibit intellectual disability (ID). The overall presentation is variable, however, and the emerging clinical picture is still evolving. A detailed phenotypic analysis of 34 XGS individuals revealed five core phenotypes (delayed motor milestones, speech delay, low muscle tone, ID, and hypotonia) in more than 80\% of individuals and an additional 12 features that occurred more variably. Seizures and scoliosis were more frequently associated with truncations that arise before the midpoint of the protein although the occurrence of most features could not be predicted by the mutation position. Transient expression of wild type and different patient truncated AHDC1 protein forms in human cell lines revealed abnormal patterns of nuclear localization including a diffuse distribution of a short truncated form and nucleolar aggregation in mid-protein truncated forms. Overall, both the occurrence of variable phenotypes and the different distribution of the expressed protein reflect the heterogeneity of this syndrome.

}, issn = {1098-1004}, doi = {10.1002/humu.24190}, author = {Khayat, Michael M and Li, He and Chander, Varuna and Hu, Jianhong and Hansen, Adam W and Li, Shoudong and Traynelis, Josh and Shen, Hua and Weissenberger, George and Stossi, Fabio and Johnson, Hannah L and Lupski, James R and Posey, Jennifer E and Sabo, Aniko and Meng, Qingchang and Murdock, David R and Wangler, Michael and Gibbs, Richard A} } @article {106, 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 {128, title = {Phenotypic expansion in KIF1A-related dominant disorders: A description of novel variants and review of published cases.}, journal = {Hum Mutat}, volume = {41}, year = {2020}, month = {2020 12}, pages = {2094-2104}, abstract = {

KIF1A is a molecular motor for membrane-bound cargo important to the development and survival of sensory neurons. KIF1A dysfunction has been associated with several Mendelian disorders with a spectrum of overlapping phenotypes, ranging from spastic paraplegia to intellectual disability. We present a novel pathogenic in-frame deletion in the KIF1A molecular motor domain inherited by two affected siblings from an unaffected mother with apparent germline mosaicism. We identified eight additional cases with heterozygous, pathogenic KIF1A variants ascertained from a local data lake. Our data provide evidence for the expansion of KIF1A-associated phenotypes to include hip subluxation and dystonia~as well as phenotypes observed in only a single case: gelastic cataplexy, coxa valga, and double collecting system. We review the literature and suggest that KIF1A dysfunction is better understood as a single neuromuscular disorder with variable involvement of other organ systems than a set of discrete disorders converging at a single locus.

}, issn = {1098-1004}, doi = {10.1002/humu.24118}, author = {Montenegro-Garreaud, Ximena and Hansen, Adam W and Khayat, Michael M and Chander, Varuna and Grochowski, Christopher M and Jiang, Yunyun and Li, He and Mitani, Tadahiro and Kessler, Elena and Jayaseelan, Joy and Shen, Hua and Gezdirici, Alper and Pehlivan, Davut and Meng, Qingchang and Rosenfeld, Jill A and Jhangiani, Shalini N and Madan-Khetarpal, Suneeta and Scott, Daryl A and Abarca-Barriga, Hugo and Trubnykova, Milana and Gingras, Marie-Claude and Muzny, Donna M and Posey, Jennifer E and Liu, Pengfei and Lupski, James R and Gibbs, Richard A} } @article {48, title = {The phenotypic spectrum of Xia-Gibbs syndrome.}, journal = {Am J Med Genet A}, volume = {176}, year = {2018}, month = {2018 06}, pages = {1315-1326}, abstract = {

Xia-Gibbs syndrome (XGS: OMIM $\#$ 615829) results from de novo truncating mutations within the AT-Hook DNA Binding Motif Containing 1 gene (AHDC1). To further define the phenotypic and molecular spectrum of this disorder, we established an XGS Registry and recruited patients from a worldwide pool of approximately 60 probands. Additional de novo truncating mutations were observed among 25 individuals, extending both the known number of mutation sites and the range of positions within the coding region that were sensitive to alteration. Detailed phenotypic examination of 20 of these patients via clinical records review and data collection from additional surveys showed a wider age range than previously described. Data from developmental milestones showed evidence for delayed speech and that males were more severely affected. Neuroimaging from six available patients showed an associated thinning of the corpus callosum and posterior fossa cysts. An increased risk of both scoliosis and seizures relative to the population burden was also observed. Data from a modified autism screening tool revealed that XGS shares significant overlap with autism spectrum disorders. These details of the phenotypic heterogeneity of XGS implicate specific genotype/phenotype correlations and suggest potential clinical management guidelines.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.38699}, author = {Jiang, Yunyun and Wangler, Michael F and McGuire, Amy L and Lupski, James R and Posey, Jennifer E and Khayat, Michael M and Murdock, David R and Sanchez-Pulido, Luis and Ponting, Chris P and Xia, Fan and Hunter, Jill V and Meng, Qingchang and Murugan, Mullai and Gibbs, Richard A} }