@article {758, title = {Biallelic GRM7 variants cause epilepsy, microcephaly, and cerebral atrophy.}, journal = {Ann Clin Transl Neurol}, volume = {7}, year = {2020}, month = {2020 05}, pages = {610-627}, abstract = {

OBJECTIVE: Defects in ion channels and neurotransmitter receptors are implicated in developmental and epileptic encephalopathy (DEE). Metabotropic glutamate receptor 7 (mGluR7), encoded by GRM7, is a presynaptic G-protein-coupled glutamate receptor critical for synaptic transmission. We previously proposed GRM7 as a candidate disease gene in two families with neurodevelopmental disorders (NDDs). One additional family has been published since. Here, we describe three additional families with GRM7 biallelic variants and deeply characterize the associated clinical neurological and electrophysiological phenotype and molecular data in 11 affected individuals from six unrelated families.

METHODS: Exome sequencing and family-based rare variant analyses on a cohort of 220 consanguineous families with NDDs revealed three families with GRM7 biallelic variants; three additional families were identified through literature search and collaboration with a clinical molecular laboratory.

RESULTS: We compared the observed clinical features and variants of 11 affected individuals from the six unrelated families. Identified novel deleterious variants included two homozygous missense variants (c.2671G>A:p.Glu891Lys and c.1973G>A:p.Arg685Gln) and one homozygous stop-gain variant (c.1975C>T:p.Arg659Ter). Developmental delay, neonatal- or infantile-onset epilepsy, and microcephaly were universal. Three individuals had hypothalamic-pituitary-axis dysfunction without pituitary structural abnormality. Neuroimaging showed cerebral atrophy and hypomyelination in a majority of cases. Two siblings demonstrated progressive loss of myelination by 2~years in both and an acquired microcephaly pattern in one. Five individuals died in early or late childhood.

CONCLUSION: Detailed clinical characterization of 11 individuals from six unrelated families demonstrates that rare biallelic GRM7 pathogenic variants can cause DEEs, microcephaly, hypomyelination, and cerebral atrophy.

}, keywords = {Adolescent, Alleles, Atrophy, Child, Child, Preschool, Cohort Studies, Consanguinity, Epilepsy, Female, Humans, Infant, Male, Microcephaly, Neurodevelopmental Disorders, Pedigree, Phenotype, Receptors, Metabotropic Glutamate, Whole Exome Sequencing}, issn = {2328-9503}, doi = {10.1002/acn3.51003}, author = {Marafi, Dana and Mitani, Tadahiro and Isikay, Sedat and Hertecant, Jozef and Almannai, Mohammed and Manickam, Kandamurugu and Abou Jamra, Rami and El-Hattab, Ayman W and Rajah, Jaishen and Fatih, Jawid M and Du, Haowei and Karaca, Ender and Bayram, Yavuz and Punetha, Jaya and Rosenfeld, Jill A and Jhangiani, Shalini N and Boerwinkle, Eric and Akdemir, Zeynep C and Erdin, Serkan and Hunter, Jill V and Gibbs, Richard A and Pehlivan, Davut and Posey, Jennifer E and Lupski, James R} } @article {573, title = {Biallelic VARS variants cause developmental encephalopathy with microcephaly that is recapitulated in vars knockout zebrafish.}, journal = {Nat Commun}, volume = {10}, year = {2019}, month = {2019 02 12}, pages = {708}, abstract = {

Aminoacyl tRNA synthetases (ARSs) link specific amino acids with their cognate transfer RNAs in a critical early step of protein translation. Mutations in ARSs have emerged as a cause of recessive, often complex neurological disease traits. Here we report an allelic series consisting of seven novel and two previously reported biallelic variants in valyl-tRNA synthetase (VARS) in ten patients with a developmental encephalopathy with microcephaly, often associated with early-onset epilepsy. In silico, in vitro, and yeast complementation assays demonstrate that the underlying pathomechanism of these mutations is most likely a loss of protein function. Zebrafish modeling accurately recapitulated some of the key neurological disease traits. These results provide both genetic and biological insights into neurodevelopmental disease and pave the way for further in-depth research on ARS related recessive disorders and precision therapies.

}, keywords = {Alleles, Animals, Brain Diseases, Cell Line, Disease Models, Animal, Epilepsy, Female, Fibroblasts, Gene Knockout Techniques, Genetic Predisposition to Disease, Humans, Loss of Function Mutation, Male, Microcephaly, Models, Molecular, Neurodevelopmental Disorders, Pedigree, Prosencephalon, Valine-tRNA Ligase, Zebrafish}, issn = {2041-1723}, doi = {10.1038/s41467-018-07953-w}, author = {Siekierska, Aleksandra and Stamberger, Hannah and Deconinck, Tine and Oprescu, Stephanie N and Partoens, Mich{\`e}le and Zhang, Yifan and Sourbron, Jo and Adriaenssens, Elias and Mullen, Patrick and Wiencek, Patrick and Hardies, Katia and Lee, Jeong-Soo and Giong, Hoi-Khoanh and Distelmaier, Felix and Elpeleg, Orly and Helbig, Katherine L and Hersh, Joseph and Isikay, Sedat and Jordan, Elizabeth and Karaca, Ender and Kecskes, Angela and Lupski, James R and Kovacs-Nagy, Reka and May, Patrick and Narayanan, Vinodh and Pendziwiat, Manuela and Ramsey, Keri and Rangasamy, Sampathkumar and Shinde, Deepali N and Spiegel, Ronen and Timmerman, Vincent and von Spiczak, Sarah and Helbig, Ingo and Weckhuysen, Sarah and Francklyn, Christopher and Antonellis, Anthony and de Witte, Peter and De Jonghe, Peter} } @article {672, title = {The Genomics of Arthrogryposis, a Complex Trait: Candidate Genes and Further Evidence for Oligogenic Inheritance.}, journal = {Am J Hum Genet}, volume = {105}, year = {2019}, month = {2019 Jul 03}, pages = {132-150}, abstract = {

Arthrogryposis is a clinical finding that is present either as a feature of a neuromuscular condition or as part of a systemic disease in over 400 Mendelian conditions. The underlying molecular etiology remains largely unknown because of genetic and phenotypic heterogeneity. We applied exome sequencing (ES) in a cohort of 89 families with the clinical sign of arthrogryposis. Additional molecular techniques including array comparative genomic hybridization (aCGH) and Droplet Digital PCR (ddPCR) were performed on individuals who were found to have pathogenic copy number variants (CNVs) and mosaicism, respectively. A molecular diagnosis was established in 65.2\% (58/89) of families. Eleven out of 58 families (19.0\%) showed evidence for potential involvement of pathogenic variation at more than one locus, probably driven by absence of heterozygosity (AOH) burden due to identity-by-descent (IBD). RYR3, MYOM2, ERGIC1, SPTBN4, and ABCA7 represent genes, identified in two or more families, for which mutations are probably causative for arthrogryposis. We also provide evidence for the involvement of CNVs in the etiology of arthrogryposis and for the idea that both mono-allelic and bi-allelic variants in the same gene cause either similar or distinct syndromes. We were able to identify the molecular etiology in nine out of 20 families who underwent reanalysis. In summary, our data from family-based ES further delineate the molecular etiology of arthrogryposis, yielded several candidate disease-associated genes, and provide evidence for mutational burden in a biological pathway or network. Our study also highlights the importance of reanalysis of individuals with unsolved diagnoses in conjunction with sequencing extended family members.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.05.015}, author = {Pehlivan, Davut and Bayram, Yavuz and Gunes, Nilay and Coban Akdemir, Zeynep and Shukla, Anju and Bierhals, Tatjana and Tabakci, Burcu and Sahin, Yavuz and Gezdirici, Alper and Fatih, Jawid M and Gulec, Elif Yilmaz and Yesil, G{\"o}zde and Punetha, Jaya and Ocak, Zeynep and Grochowski, Christopher M and Karaca, Ender and Albayrak, Hatice Mutlu and Radhakrishnan, Periyasamy and Erdem, Haktan Bagis and Sahin, Ibrahim and Yildirim, Timur and Bayhan, Ilhan A and Bursali, Aysegul and Elmas, Muhsin and Yuksel, Zafer and Ozdemir, Ozturk and Silan, Fatma and Yildiz, Onur and Yesilbas, Osman and Isikay, Sedat and Balta, Burhan and Gu, Shen and Jhangiani, Shalini N and Doddapaneni, Harsha and Hu, Jianhong and Muzny, Donna M and Boerwinkle, Eric and Gibbs, Richard A and Tsiakas, Konstantinos and Hempel, Maja and Girisha, Katta Mohan and Gul, Davut and Posey, Jennifer E and Elcioglu, Nursel H and Tuysuz, Beyhan and Lupski, James R} } @article {740, title = {Mutations in ANKLE2, a ZIKA Virus Target, Disrupt an Asymmetric Cell Division Pathway in Drosophila Neuroblasts to Cause Microcephaly.}, journal = {Dev Cell}, volume = {51}, year = {2019}, month = {2019 Dec 16}, pages = {713-729.e6}, abstract = {

The apical Par complex, which contains atypical protein kinase C (aPKC), Bazooka (Par-3), and Par-6, is required for establishing polarity during asymmetric division of neuroblasts in Drosophila, and its activity depends on L(2)gl. We show that loss of Ankle2, a protein associated with microcephaly in humans and known to interact with Zika protein NS4A, reduces brain volume in flies and impacts the function of the Par complex. Reducing Ankle2 levels disrupts endoplasmic reticulum (ER) and nuclear envelope morphology, releasing the kinase Ballchen-VRK1 into the cytosol. These defects are associated with reduced phosphorylation of aPKC, disruption of Par-complex localization, and spindle alignment defects. Importantly, removal of one copy of ballchen or l(2)gl suppresses Ankle2 mutant phenotypes and restores viability and brain size. Human mutational studies implicate the above-mentioned genes in microcephaly and motor neuron disease. We suggest that NS4A, ANKLE2, VRK1, and LLGL1 define a pathway impinging on asymmetric determinants of neural stem cell division.

}, issn = {1878-1551}, doi = {10.1016/j.devcel.2019.10.009}, author = {Link, Nichole and Chung, Hyunglok and Jolly, Angad and Withers, Marjorie and Tepe, Burak and Arenkiel, Benjamin R and Shah, Priya S and Krogan, Nevan J and Aydin, Hatip and Geckinli, Bilgen B and Tos, Tulay and Isikay, Sedat and Tuysuz, Beyhan and Mochida, Ganesh H and Thomas, Ajay X and Clark, Robin D and Mirzaa, Ghayda M and Lupski, James R and Bellen, Hugo J} } @article {562, title = {Bi-allelic CCDC47 Variants Cause a Disorder Characterized by Woolly Hair, Liver Dysfunction, Dysmorphic Features, and Global Developmental Delay.}, journal = {Am J Hum Genet}, volume = {103}, year = {2018}, month = {2018 11 01}, pages = {794-807}, abstract = {

Ca signaling is vital for various cellular processes including synaptic vesicle exocytosis, muscle contraction, regulation of secretion, gene transcription, and cellular proliferation. The endoplasmic reticulum (ER) is the largest intracellular Ca store, and dysregulation of ER Ca signaling and homeostasis contributes to the pathogenesis of various complex disorders and Mendelian disease traits. We describe four unrelated individuals with a complex multisystem disorder characterized by woolly hair, liver dysfunction, pruritus, dysmorphic features, hypotonia, and global developmental delay. Through whole-exome sequencing and family-based genomics, we identified bi-allelic variants in CCDC47 that encodes the Ca-binding ER transmembrane protein CCDC47. CCDC47, also known as calumin, has been shown to bind Ca with low affinity and high capacity. In mice, loss of Ccdc47 leads to embryonic lethality, suggesting that Ccdc47 is essential for early development. Characterization of cells from individuals with predicted likely damaging alleles showed decreased CCDC47 mRNA expression and protein levels. In~vitro cellular experiments showed decreased total ER Ca storage, impaired Ca signaling mediated by the IPR Ca release channel, and reduced ER Ca refilling via store-operated Ca entry. These results, together with the previously described role of CCDC47 in Ca signaling and development, suggest that bi-allelic loss-of-function variants in CCDC47 underlie the pathogenesis of this multisystem disorder.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.09.014}, author = {Morimoto, Marie and Waller-Evans, Helen and Ammous, Zineb and Song, Xiaofei and Strauss, Kevin A and Pehlivan, Davut and Gonzaga-Jauregui, Claudia and Puffenberger, Erik G and Holst, Charles R and Karaca, Ender and Brigatti, Karlla W and Maguire, Emily and Coban-Akdemir, Zeynep H and Amagata, Akiko and Lau, C Christopher and Chepa-Lotrea, Xenia and Macnamara, Ellen and Tos, Tulay and Isikay, Sedat and Nehrebecky, Michele and Overton, John D and Klein, Matthew and Markello, Thomas C and Posey, Jennifer E and Adams, David R and Lloyd-Evans, Emyr and Lupski, James R and Gahl, William A and Malicdan, May Christine V} } @article {612, title = {Phenotypic expansion illuminates multilocus pathogenic variation.}, journal = {Genet Med}, volume = {20}, year = {2018}, month = {2018 12}, pages = {1528-1537}, abstract = {

PURPOSE: Multilocus variation-pathogenic variants in two or more disease genes-can potentially explain the underlying genetic basis for apparent phenotypic expansion in cases for which the observed clinical features extend beyond those reported in association with a "known" disease gene.

METHODS: Analyses focused on 106 patients, 19 for whom apparent phenotypic expansion was previously attributed to variation at known disease genes. We performed a retrospective computational reanalysis of whole-exome sequencing data using stringent Variant Call File filtering criteria to determine whether molecular diagnoses involving additional disease loci might explain the observed expanded phenotypes.

RESULTS: Multilocus variation was identified in 31.6\% (6/19) of families with phenotypic expansion and 2.3\% (2/87) without phenotypic expansion. Intrafamilial clinical variability within two families was explained by multilocus variation identified in the more severely affected sibling.

CONCLUSION: Our findings underscore the role of multiple rare variants at different loci in the etiology of genetically and clinically heterogeneous cohorts. Intrafamilial phenotypic and genotypic variability allowed a dissection of genotype-phenotype relationships in two families. Our data emphasize the critical role of the clinician in diagnostic genomic analyses and demonstrate that apparent phenotypic expansion may represent blended phenotypes resulting from pathogenic variation at more than one locus.

}, issn = {1530-0366}, doi = {10.1038/gim.2018.33}, author = {Karaca, Ender and Posey, Jennifer E and Coban Akdemir, Zeynep and Pehlivan, Davut and Harel, Tamar and Jhangiani, Shalini N and Bayram, Yavuz and Song, Xiaofei and Bahrambeigi, Vahid and Yuregir, Ozge Ozalp and Bozdogan, Sevcan and Yesil, G{\"o}zde and Isikay, Sedat and Muzny, Donna and Gibbs, Richard A and Lupski, James R} } @article {95, title = {Molecular etiology of arthrogryposis in multiple families of mostly Turkish origin.}, journal = {J Clin Invest}, volume = {126}, year = {2016}, month = {2016 Feb}, pages = {762-78}, abstract = {

BACKGROUND: Arthrogryposis, defined as congenital joint contractures in 2 or more body areas, is a clinical sign rather than a specific disease diagnosis. To date, more than 400 different disorders have been described that present with arthrogryposis, and variants of more than 220 genes have been associated with these disorders; however, the underlying molecular etiology remains unknown in the considerable majority of these cases.

METHODS: We performed whole exome sequencing (WES) of 52 patients with clinical presentation of arthrogryposis from 48 different families.

RESULTS: Affected individuals from 17 families (35.4\%) had variants in known arthrogryposis-associated genes, including homozygous variants of cholinergic γ nicotinic receptor (CHRNG, 6 subjects) and endothelin converting enzyme-like 1 (ECEL1, 4 subjects). Deleterious variants in candidate arthrogryposis-causing genes (fibrillin 3 [FBN3], myosin IXA [MYO9A], and pleckstrin and Sec7 domain containing 3 [PSD3]) were identified in 3 families (6.2\%). Moreover, in 8 families with a homozygous mutation in an arthrogryposis-associated gene, we identified a second locus with either a homozygous or compound heterozygous variant in a candidate gene (myosin binding protein C, fast type [MYBPC2] and vacuolar protein sorting 8 [VPS8], 2 families, 4.2\%) or in another disease-associated genes (6 families, 12.5\%), indicating a potential mutational burden contributing to disease expression.

CONCLUSION: In 58.3\% of families, the arthrogryposis manifestation could be explained by a molecular diagnosis; however, the molecular etiology in subjects from 20 families remained unsolved by WES. Only 5 of these 20 unrelated subjects had a clinical presentation consistent with amyoplasia; a phenotype not thought to be of genetic origin. Our results indicate that increased use of genome-wide technologies will provide opportunities to better understand genetic models for diseases and molecular mechanisms of genetically heterogeneous disorders, such as arthrogryposis.

FUNDING: This work was supported in part by US National Human Genome Research Institute (NHGRI)/National Heart, Lung, and Blood Institute (NHLBI) grant U54HG006542 to the Baylor-Hopkins Center for Mendelian Genomics, and US National Institute of Neurological Disorders and Stroke (NINDS) grant R01NS058529 to J.R. Lupski.

}, keywords = {Arthrogryposis, Exome, Family, Female, Genome-Wide Association Study, Humans, Male, Turkey}, issn = {1558-8238}, doi = {10.1172/JCI84457}, author = {Bayram, Yavuz and Karaca, Ender and Coban Akdemir, Zeynep and Yilmaz, Elif Ozdamar and Tayfun, Gulsen Akay and Aydin, Hatip and Torun, Deniz and Bozdogan, Sevcan Tug and Gezdirici, Alper and Isikay, Sedat and Atik, Mehmed M and Gambin, Tomasz and Harel, Tamar and El-Hattab, Ayman W and Charng, Wu-Lin and Pehlivan, Davut and Jhangiani, Shalini N and Muzny, Donna M and Karaman, Ali and Celik, Tamer and Yuregir, Ozge Ozalp and Yildirim, Timur and Bayhan, Ilhan A and Boerwinkle, Eric and Gibbs, Richard A and Elcioglu, Nursel and Tuysuz, Beyhan and Lupski, James R} } @article {121, title = {Genes that Affect Brain Structure and Function Identified by Rare Variant Analyses of Mendelian Neurologic Disease.}, journal = {Neuron}, volume = {88}, year = {2015}, month = {2015 Nov 04}, pages = {499-513}, abstract = {

Development of the human nervous system involves complex interactions among fundamental cellular processes and requires a multitude of genes, many of which remain to be associated with human disease. We applied whole exome sequencing to 128 mostly consanguineous families with neurogenetic disorders that often included brain malformations. Rare variant analyses for both single nucleotide variant (SNV) and copy number variant (CNV) alleles allowed for identification of 45 novel variants in 43 known disease genes, 41 candidate genes, and CNVs in 10 families, with an overall potential molecular cause identified in >85\% of families studied. Among the candidate genes identified, we found PRUNE, VARS, and DHX37 in multiple families and homozygous loss-of-function variants in AGBL2, SLC18A2, SMARCA1, UBQLN1, and CPLX1. Neuroimaging and in silico analysis of functional and expression proximity between candidate and known disease genes allowed for further understanding of genetic networks underlying specific types of brain malformations.

}, keywords = {Brain, Cohort Studies, Databases, Genetic, Female, Gene Regulatory Networks, Genetic Association Studies, Genetic Variation, Humans, Male, Mendelian Randomization Analysis, Nervous System Diseases, Pedigree}, issn = {1097-4199}, doi = {10.1016/j.neuron.2015.09.048}, author = {Karaca, Ender and Harel, Tamar and Pehlivan, Davut and Jhangiani, Shalini N and Gambin, Tomasz and Coban Akdemir, Zeynep and Gonzaga-Jauregui, Claudia and Erdin, Serkan and Bayram, Yavuz and Campbell, Ian M and Hunter, Jill V and Atik, Mehmed M and Van Esch, Hilde and Yuan, Bo and Wiszniewski, Wojciech and Isikay, Sedat and Yesil, G{\"o}zde and Yuregir, Ozge O and Tug Bozdogan, Sevcan and Aslan, Huseyin and Aydin, Hatip and Tos, Tulay and Aksoy, Ayse and De Vivo, Darryl C and Jain, Preti and Geckinli, B Bilge and Sezer, Ozlem and Gul, Davut and Durmaz, Burak and Cogulu, Ozgur and Ozkinay, Ferda and Topcu, Vehap and Candan, Sukru and Cebi, Alper Han and Ikbal, Mevlit and Yilmaz Gulec, Elif and Gezdirici, Alper and Koparir, Erkan and Ekici, Fatma and Coskun, Salih and Cicek, Salih and Karaer, Kadri and Koparir, Asuman and Duz, Mehmet Bugrahan and Kirat, Emre and Fenercioglu, Elif and Ulucan, Hakan and Seven, Mehmet and Guran, Tulay and Elcioglu, Nursel and Yildirim, Mahmut Selman and Aktas, Dilek and Alika{\c s}ifo{\u g}lu, Mehmet and Ture, Mehmet and Yakut, Tahsin and Overton, John D and Yuksel, Adnan and Ozen, Mustafa and Muzny, Donna M and Adams, David R and Boerwinkle, Eric and Chung, Wendy K and Gibbs, Richard A and Lupski, James R} } @article {253, title = {Human CLP1 mutations alter tRNA biogenesis, affecting both peripheral and central nervous system function.}, journal = {Cell}, volume = {157}, year = {2014}, month = {2014 Apr 24}, pages = {636-50}, abstract = {

CLP1 is a RNA kinase involved in tRNA splicing. Recently, CLP1 kinase-dead mice were shown to display a neuromuscular disorder with loss of motor neurons and muscle paralysis. Human genome analyses now identified a CLP1 homozygous missense mutation (p.R140H) in five unrelated families, leading to a loss of CLP1 interaction with the tRNA splicing endonuclease (TSEN) complex, largely reduced pre-tRNA cleavage activity, and accumulation of linear tRNA introns. The affected individuals develop severe motor-sensory defects, cortical dysgenesis, and microcephaly. Mice carrying kinase-dead CLP1 also displayed microcephaly and reduced cortical brain volume due to the enhanced cell death of neuronal progenitors that is associated with reduced numbers of cortical neurons. Our data elucidate a neurological syndrome defined by CLP1 mutations that impair tRNA splicing. Reduction of a founder mutation to homozygosity illustrates the importance of rare variations in disease and supports the clan genomics hypothesis.

}, keywords = {Abnormalities, Multiple, Animals, Central Nervous System Diseases, Cerebrum, Child, Preschool, Endoribonucleases, Female, Fibroblasts, Humans, Infant, Male, Mice, Mice, Inbred CBA, Microcephaly, Mutation, Missense, Nuclear Proteins, Peripheral Nervous System Diseases, Phosphotransferases, RNA, Transfer, Transcription Factors}, issn = {1097-4172}, doi = {10.1016/j.cell.2014.02.058}, author = {Karaca, Ender and Weitzer, Stefan and Pehlivan, Davut and Shiraishi, Hiroshi and Gogakos, Tasos and Hanada, Toshikatsu and Jhangiani, Shalini N and Wiszniewski, Wojciech and Withers, Marjorie and Campbell, Ian M and Erdin, Serkan and Isikay, Sedat and Franco, Luis M and Gonzaga-Jauregui, Claudia and Gambin, Tomasz and Gelowani, Violet and Hunter, Jill V and Yesil, G{\"o}zde and Koparir, Erkan and Yilmaz, Sarenur and Brown, Miguel and Briskin, Daniel and Hafner, Markus and Morozov, Pavel and Farazi, Thalia A and Bernreuther, Christian and Glatzel, Markus and Trattnig, Siegfried and Friske, Joachim and Kronnerwetter, Claudia and Bainbridge, Matthew N and Gezdirici, Alper and Seven, Mehmet and Muzny, Donna M and Boerwinkle, Eric and Ozen, Mustafa and Clausen, Tim and Tuschl, Thomas and Yuksel, Adnan and Hess, Andreas and Gibbs, Richard A and Martinez, Javier and Penninger, Josef M and Lupski, James R} }