@article {941, title = {MED27 Variants Cause Developmental Delay, Dystonia, and Cerebellar Hypoplasia.}, journal = {Ann Neurol}, volume = {89}, year = {2021}, month = {2021 04}, pages = {828-833}, abstract = {

The Mediator multiprotein complex functions as a regulator of RNA polymerase II-catalyzed gene transcription. In this study, exome sequencing detected biallelic putative disease-causing variants in MED27, encoding Mediator complex subunit 27, in 16 patients from 11 families with a novel neurodevelopmental syndrome. Patient phenotypes are highly homogeneous, including global developmental delay, intellectual disability, axial hypotonia with distal spasticity, dystonic movements, and cerebellar hypoplasia. Seizures and cataracts were noted in severely affected individuals. Identification of multiple patients with biallelic MED27 variants supports the critical role of MED27 in normal human neural development, particularly for the cerebellum. ANN NEUROL 2021;89:828-833.

}, keywords = {Adolescent, Adult, Amino Acid Sequence, Cataract, Cerebellum, Child, Child, Preschool, Developmental Disabilities, Dystonia, Epilepsy, Genetic Variation, Humans, Infant, Mediator Complex, Nervous System Malformations, Phenotype, Whole Exome Sequencing}, issn = {1531-8249}, doi = {10.1002/ana.26019}, author = {Meng, Linyan and Isohanni, Pirjo and Shao, Yunru and GrAHm, Brett H and Hickey, Scott E and Brooks, Stephanie and Suomalainen, Anu and Joset, Pascal and Steindl, Katharina and Rauch, Anita and Hackenberg, Annette and High, Frances A and Armstrong-Javors, Amy and Mencacci, Niccol{\`o} E and Gonz{\`a}lez-Latapi, Paulina and Kamel, Walaa A and Al-Hashel, Jasem Y and Bustos, Bernab{\'e} I and Hernandez, Alejandro V and Krainc, Dimitri and Lubbe, Steven J and Van Esch, Hilde and De Luca, Chiara and Ballon, Katleen and Ravelli, Claudia and Burglen, Lydie and Qebibo, Leila and Calame, Daniel G and Mitani, Tadahiro and Marafi, Dana and Pehlivan, Davut and Saadi, Nebal W and Sahin, Yavuz and Maroofian, Reza and Efthymiou, Stephanie and Houlden, Henry and Maqbool, Shazia and Rahman, Fatima and Gu, Shen and Posey, Jennifer E and Lupski, James R and Hunter, Jill V and Wangler, Michael F and Carroll, Christopher J and Yang, Yaping} } @article {624, title = {Ari-1 Regulates Myonuclear Organization Together with Parkin and Is Associated with Aortic Aneurysms.}, journal = {Dev Cell}, volume = {45}, year = {2018}, month = {2018 04 23}, pages = {226-244.e8}, abstract = {

Nuclei are actively positioned and anchored to the cytoskeleton via the LINC (Linker of Nucleoskeleton and Cytoskeleton) complex. We identified mutations in the Parkin-like E3 ubiquitin ligase Ariadne-1 (Ari-1) that affect the localization and distribution of LINC~complex members in Drosophila. ari-1 mutants exhibit nuclear clustering and morphology defects in larval muscles. We show that Ari-1 mono-ubiquitinates the core LINC complex member Koi. Surprisingly, we discovered functional redundancy between Parkin and Ari-1: increasing Parkin expression rescues ari-1 mutant phenotypes and vice versa. We further show that rare variants in the human homolog of ari-1 (ARIH1) are associated with thoracic aortic aneurysms and dissections, conditions resulting from smooth muscle cell (SMC) dysfunction. Human ARIH1 rescues fly ari-1 mutant phenotypes, whereas human variants found in patients fail to do so. In addition, SMCs obtained from patients display aberrant nuclear morphology. Hence, ARIH1 is critical in anchoring myonuclei to the cytoskeleton.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Animals, Aortic Aneurysm, Carrier Proteins, Cell Nucleus, Child, Preschool, Cytoskeleton, Drosophila melanogaster, Drosophila Proteins, Female, Humans, Male, Middle Aged, Mutation, Myocytes, Smooth Muscle, Pedigree, Phenotype, Ubiquitin-Protein Ligases, Young Adult}, issn = {1878-1551}, doi = {10.1016/j.devcel.2018.03.020}, author = {Tan, Kai Li and Haelterman, Nele A and Kwartler, Callie S and Regalado, Ellen S and Lee, Pei-Tseng and Nagarkar-Jaiswal, Sonal and Guo, Dong-Chuan and Duraine, Lita and Wangler, Michael F and Bamshad, Michael J and Nickerson, Deborah A and Lin, Guang and Milewicz, Dianna M and Bellen, Hugo J} } @article {637, title = {Clinically severe CACNA1A alleles affect synaptic function and neurodegeneration differentially.}, journal = {PLoS Genet}, volume = {13}, year = {2017}, month = {2017 Jul}, pages = {e1006905}, abstract = {

Dominant mutations in CACNA1A, encoding the α-1A subunit of the neuronal P/Q type voltage-dependent Ca2+ channel, can cause diverse neurological phenotypes. Rare cases of markedly severe early onset developmental delay and congenital ataxia can be due to de novo CACNA1A missense alleles, with variants affecting the S4 transmembrane segments of the channel, some of which are reported to be loss-of-function. Exome sequencing in five individuals with severe early onset ataxia identified one novel variant (p.R1673P), in a girl with global developmental delay and progressive cerebellar atrophy, and a recurrent, de novo p.R1664Q variant, in four individuals with global developmental delay, hypotonia, and ophthalmologic abnormalities. Given the severity of these phenotypes we explored their functional impact in Drosophila. We previously generated null and partial loss-of-function alleles of cac, the homolog of CACNA1A in Drosophila. Here, we created transgenic wild type and mutant genomic rescue constructs with the two noted conserved point mutations. The p.R1673P mutant failed to rescue cac lethality, displayed a gain-of-function phenotype in electroretinograms (ERG) recorded from mutant clones, and evolved a neurodegenerative phenotype in aging flies, based on ERGs and transmission electron microscopy. In contrast, the p.R1664Q variant exhibited loss of function and failed to develop a neurodegenerative phenotype. Hence, the novel R1673P allele produces neurodegenerative phenotypes in flies and human, likely due to a toxic gain of function.

}, keywords = {Alleles, Animals, Animals, Genetically Modified, Calcium Channels, Cerebellar Ataxia, Child, Child, Preschool, Drosophila melanogaster, Female, Genome, Human, Genome-Wide Association Study, Humans, Male, Microscopy, Electron, Transmission, Mutation, Missense, Neurodegenerative Diseases, Neuroimaging, Phenotype, Point Mutation}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1006905}, author = {Luo, Xi and Rosenfeld, Jill A and Yamamoto, Shinya and Harel, Tamar and Zuo, Zhongyuan and Hall, Melissa and Wierenga, Klaas J and Pastore, Matthew T and Bartholomew, Dennis and Delgado, Mauricio R and Rotenberg, Joshua and Lewis, Richard Alan and Emrick, Lisa and Bacino, Carlos A and Eldomery, Mohammad K and Coban Akdemir, Zeynep and Xia, Fan and Yang, Yaping and Lalani, Seema R and Lotze, Timothy and Lupski, James R and Lee, Brendan and Bellen, Hugo J and Wangler, Michael F} } @article {334, title = {A Recurrent De Novo Variant in NACC1 Causes a Syndrome Characterized by Infantile Epilepsy, Cataracts, and Profound Developmental Delay.}, journal = {Am J Hum Genet}, volume = {100}, year = {2017}, month = {2017 Feb 02}, pages = {343-351}, abstract = {

Whole-exome sequencing (WES) has increasingly enabled new pathogenic gene variant identification for undiagnosed neurodevelopmental disorders and provided insights into both gene function and disease biology. Here, we describe seven children with a neurodevelopmental disorder characterized by microcephaly, profound developmental delays and/or intellectual disability, cataracts, severe epilepsy including infantile spasms, irritability, failure to thrive, and stereotypic hand movements. Brain imaging in these individuals reveals delay in myelination and cerebral atrophy. We observe an identical recurrent de novo heterozygous c.892C>T (p.Arg298Trp) variant in the nucleus accumbens associated 1 (NACC1) gene in seven affected individuals. One of the seven individuals is mosaic for this variant. NACC1 encodes a transcriptional repressor implicated in gene expression and has not previously been associated with germline disorders. The probability of finding the same missense NACC1 variant by chance in 7 out of 17,228 individuals who~underwent WES for diagnoses of neurodevelopmental phenotypes is extremely small and achieves genome-wide significance (p~= 1.25~{\texttimes} 10). Selective constraint against missense variants in NACC1 makes this excess of an identical missense variant in all seven individuals more remarkable. Our findings are consistent with a germline recurrent mutational hotspot associated with an allele-specific neurodevelopmental phenotype in NACC1.

}, keywords = {Alleles, Amino Acid Sequence, Brain, Cataract, Child, Child, Preschool, Female, Genetic Variation, Genome-Wide Association Study, Humans, Infant, Intellectual Disability, Magnetic Resonance Imaging, Male, Microcephaly, Mutation, Missense, Neoplasm Proteins, Pedigree, Phenotype, Repressor Proteins, Spasms, Infantile}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.12.013}, author = {Schoch, Kelly and Meng, Linyan and Szelinger, Szabolcs and Bearden, David R and Stray-Pedersen, Asbjorg and Busk, Oyvind L and Stong, Nicholas and Liston, Eriskay and Cohn, Ronald D and Scaglia, Fernando and Rosenfeld, Jill A and Tarpinian, Jennifer and Skraban, Cara M and Deardorff, Matthew A and Friedman, Jeremy N and Akdemir, Zeynep Coban and Walley, Nicole and Mikati, Mohamad A and Kranz, Peter G and Jasien, Joan and McConkie-Rosell, Allyn and McDonald, Marie and Wechsler, Stephanie Burns and Freemark, Michael and Kansagra, Sujay and Freedman, Sharon and Bali, Deeksha and Millan, Francisca and Bale, Sherri and Nelson, Stanley F and Lee, Hane and Dorrani, Naghmeh and Goldstein, David B and Xiao, Rui and Yang, Yaping and Posey, Jennifer E and Martinez-Agosto, Julian A and Lupski, James R and Wangler, Michael F and Shashi, Vandana} } @article {248, title = {De novo truncating mutations in AHDC1 in individuals with syndromic expressive language delay, hypotonia, and sleep apnea.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 May 01}, pages = {784-9}, abstract = {

Clinical whole-exome sequencing (WES) for identification of mutations leading to Mendelian disease has been offered to the medical community since 2011. Clinically undiagnosed neurological disorders are the most frequent basis for test referral, and currently, approximately 25\% of such cases are diagnosed at the molecular level. To date, there are approximately 4,000 "known" disease-associated loci, and many are associated with striking dysmorphic features, making genotype-phenotype correlations relatively straightforward. A significant fraction of cases, however, lack characteristic dysmorphism or clinical pathognomonic traits and are dependent upon molecular tests for definitive diagnoses. Further, many molecular diagnoses are guided by recent gene-disease association discoveries. Hence, there is a critical interplay between clinical testing and research leading to gene-disease association discovery. Here, we describe four probands, all of whom presented with hypotonia, intellectual disability, global developmental delay, and mildly dysmorphic facial features. Three of the four also had sleep apnea. Each was a simplex case without a remarkable family history. Using WES, we identified AHDC1 de novo truncating mutations that most likely cause this genetic syndrome.

}, keywords = {Child, Child, Preschool, DNA-Binding Proteins, Exome, Female, Humans, Infant, Intellectual Disability, Language Development Disorders, Male, Muscle Hypotonia, Mutation, Sleep Apnea Syndromes, Syndrome}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.04.006}, author = {Xia, Fan and Bainbridge, Matthew N and Tan, Tiong Yang and Wangler, Michael F and Scheuerle, Angela E and Zackai, Elaine H and Harr, Margaret H and Sutton, V Reid and Nalam, Roopa L and Zhu, Wenmiao and Nash, Margot and Ryan, Monique M and Yaplito-Lee, Joy and Hunter, Jill V and Deardorff, Matthew A and Penney, Samantha J and Beaudet, Arthur L and Plon, Sharon E and Boerwinkle, Eric A and Lupski, James R and Eng, Christine M and Muzny, Donna M and Yang, Yaping and Gibbs, Richard A} } @article {257, title = {Heterozygous de novo and inherited mutations in the smooth muscle actin (ACTG2) gene underlie megacystis-microcolon-intestinal hypoperistalsis syndrome.}, journal = {PLoS Genet}, volume = {10}, year = {2014}, month = {2014 Mar}, pages = {e1004258}, abstract = {

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disorder of enteric smooth muscle function affecting the intestine and bladder. Patients with this severe phenotype are dependent on total parenteral nutrition and urinary catheterization. The cause of this syndrome has remained a mystery since Berdon{\textquoteright}s initial description in 1976. No genes have been clearly linked to MMIHS. We used whole-exome sequencing for gene discovery followed by targeted Sanger sequencing in a cohort of patients with MMIHS and intestinal pseudo-obstruction. We identified heterozygous ACTG2 missense variants in 15 unrelated subjects, ten being apparent de novo mutations. Ten unique variants were detected, of which six affected CpG dinucleotides and resulted in missense mutations at arginine residues, perhaps related to biased usage of CpG containing codons within actin genes. We also found some of the same heterozygous mutations that we observed as apparent de novo mutations in MMIHS segregating in families with intestinal pseudo-obstruction, suggesting that ACTG2 is responsible for a spectrum of smooth muscle disease. ACTG2 encodes γ2 enteric actin and is the first gene to be clearly associated with MMIHS, suggesting an important role for contractile proteins in enteric smooth muscle disease.

}, keywords = {Abnormalities, Multiple, Actins, Adolescent, Adult, Child, Child, Preschool, Colon, Exome, Female, Heterozygote, Humans, Intestinal Pseudo-Obstruction, Male, Muscle, Smooth, Mutation, Urinary Bladder}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1004258}, author = {Wangler, Michael F and Gonzaga-Jauregui, Claudia and Gambin, Tomasz and Penney, Samantha and Moss, Timothy and Chopra, Atul and Probst, Frank J and Xia, Fan and Yang, Yaping and Werlin, Steven and Eglite, Ieva and Kornejeva, Liene and Bacino, Carlos A and Baldridge, Dustin and Neul, Jeff and Lehman, Efrat Lev and Larson, Austin and Beuten, Joke and Muzny, Donna M and Jhangiani, Shalini and Gibbs, Richard A and Lupski, James R and Beaudet, Arthur} }