@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 {90, title = {Recurrent Muscle Weakness with Rhabdomyolysis, Metabolic Crises, and Cardiac Arrhythmia Due to Bi-allelic TANGO2 Mutations.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Feb 04}, pages = {347-57}, abstract = {

The underlying genetic etiology of rhabdomyolysis remains elusive in a significant fraction of individuals presenting with recurrent metabolic crises and muscle weakness. Using exome sequencing, we identified bi-allelic mutations in TANGO2 encoding transport and Golgi organization 2 homolog (Drosophila) in 12 subjects with episodic rhabdomyolysis, hypoglycemia, hyperammonemia, and susceptibility to life-threatening cardiac tachyarrhythmias. A recurrent homozygous c.460G>A (p.Gly154Arg) mutation was found in four unrelated individuals of Hispanic/Latino origin, and a homozygous \~{}34 kb deletion affecting exons 3-9 was observed in two families of European ancestry. One individual of mixed Hispanic/European descent was found to be compound heterozygous for c.460G>A (p.Gly154Arg) and the deletion of exons 3-9. Additionally, a homozygous exons 4-6 deletion was identified in a consanguineous Middle Eastern Arab family. No homozygotes have been reported for these changes in control databases. Fibroblasts derived from a subject with the recurrent c.460G>A (p.Gly154Arg) mutation showed evidence of increased endoplasmic reticulum stress and a reduction in Golgi volume density in comparison to control. Our results show that the c.460G>A (p.Gly154Arg) mutation and the exons 3-9 heterozygous deletion in TANGO2 are recurrent pathogenic alleles present in the Latino/Hispanic and European populations, respectively, causing considerable morbidity in the homozygotes in these populations.

}, keywords = {Alleles, Arabs, Arrhythmias, Cardiac, Base Sequence, Child, Child, Preschool, Endoplasmic Reticulum Stress, European Continental Ancestry Group, Exome, Exons, Female, Gene Deletion, Golgi Apparatus, Hispanic Americans, Homozygote, Humans, Infant, Male, Molecular Sequence Data, Muscle Weakness, Pedigree, Rhabdomyolysis}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.12.008}, author = {Lalani, Seema R and Liu, Pengfei and Rosenfeld, Jill A and Watkin, Levi B and Chiang, Theodore and Leduc, Magalie S and Zhu, Wenmiao and Ding, Yan and Pan, Shujuan and Vetrini, Francesco and Miyake, Christina Y and Shinawi, Marwan and Gambin, Tomasz and Eldomery, Mohammad K and Akdemir, Zeynep Hande Coban and Emrick, Lisa and Wilnai, Yael and Schelley, Susan and Koenig, Mary Kay and Memon, Nada and Farach, Laura S and Coe, Bradley P and Azamian, Mahshid and Hernandez, Patricia and Zapata, Gladys and Jhangiani, Shalini N and Muzny, Donna M and Lotze, Timothy and Clark, Gary and Wilfong, Angus and Northrup, Hope and Adesina, Adekunle and Bacino, Carlos A and Scaglia, Fernando and Bonnen, Penelope E and Crosson, Jane and Duis, Jessica and Maegawa, Gustavo H B and Coman, David and Inwood, Anita and McGill, Jim and Boerwinkle, Eric and Graham, Brett and Beaudet, Art and Eng, Christine M and Hanchard, Neil A and Xia, Fan and Orange, Jordan S and Gibbs, Richard A and Lupski, James R and Yang, Yaping} } @article {211, title = {Mutations in PURA cause profound neonatal hypotonia, seizures, and encephalopathy in 5q31.3 microdeletion syndrome.}, journal = {Am J Hum Genet}, volume = {95}, year = {2014}, month = {2014 Nov 06}, pages = {579-83}, abstract = {

5q31.3 microdeletion syndrome is characterized by neonatal hypotonia, encephalopathy with or without epilepsy, and severe developmental delay, and the minimal critical deletion interval harbors three genes. We describe 11 individuals with clinical features of 5q31.3 microdeletion syndrome and de novo mutations in PURA, encoding transcriptional activator protein Pur-α, within the critical region. These data implicate causative PURA mutations responsible for the severe neurological phenotypes observed in this syndrome.

}, keywords = {Abnormalities, Multiple, Amino Acid Sequence, Animals, Base Sequence, Caenorhabditis elegans, Chromosome Deletion, Chromosome Mapping, Chromosomes, Human, Pair 5, DNA-Binding Proteins, Humans, Molecular Sequence Data, Muscle Hypotonia, Mutation, Seizures, Sequence Analysis, DNA, Syndrome, Transcription Factors}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.09.014}, author = {Lalani, Seema R and Zhang, Jing and Schaaf, Christian P and Brown, Chester W and Magoulas, Pilar and Tsai, Anne Chun-Hui and El-Gharbawy, Areeg and Wierenga, Klaas J and Bartholomew, Dennis and Fong, Chin-To and Barbaro-Dieber, Tina and Kukolich, Mary K and Burrage, Lindsay C and Austin, Elise and Keller, Kory and Pastore, Matthew and Fernandez, Fabio and Lotze, Timothy and Wilfong, Angus and Purcarin, Gabriela and Zhu, Wenmiao and Craigen, William J and McGuire, Marianne and Jain, Mahim and Cooney, Erin and Azamian, Mahshid and Bainbridge, Matthew N and Muzny, Donna M and Boerwinkle, Eric and Person, Richard E and Niu, Zhiyv and Eng, Christine M and Lupski, James R and Gibbs, Richard A and Beaudet, Arthur L and Yang, Yaping and Wang, Meng C and Xia, Fan} } @article {287, title = {Mutations in VRK1 associated with complex motor and sensory axonal neuropathy plus microcephaly.}, journal = {JAMA Neurol}, volume = {70}, year = {2013}, month = {2013 Dec}, pages = {1491-8}, abstract = {

IMPORTANCE: Patients with rare diseases and complex clinical presentations represent a challenge for clinical diagnostics. Genomic approaches are allowing the identification of novel variants in genes for very rare disorders, enabling a molecular diagnosis. Genomics is also revealing a phenotypic expansion whereby the full spectrum of clinical expression conveyed by mutant alleles at a locus can be better appreciated.

OBJECTIVE: To elucidate the molecular cause of a complex neuropathy phenotype in 3 patients by applying genomic sequencing strategies.

DESIGN, SETTING, AND PARTICIPANTS: Three affected individuals from 2 unrelated families presented with a complex neuropathy phenotype characterized by axonal sensorimotor neuropathy and microcephaly. They were recruited into the Centers for Mendelian Genomics research program to identify the molecular cause of their phenotype. Whole-genome, targeted whole-exome sequencing, and high-resolution single-nucleotide polymorphism arrays were performed in genetics clinics of tertiary care pediatric hospitals and biomedical research institutions.

MAIN OUTCOMES AND MEASURES: Whole-genome and whole-exome sequencing identified the variants responsible for the patients{\textquoteright} clinical phenotype.

RESULTS: We identified compound heterozygous alleles in 2 affected siblings from 1 family and a homozygous nonsense variant in the third unrelated patient in the vaccinia-related kinase 1 gene (VRK1). In the latter subject, we found a common haplotype on which the nonsense mutation occurred and that segregates in the Ashkenazi Jewish population.

CONCLUSIONS AND RELEVANCE: We report the identification of disease-causing alleles in 3 children from 2 unrelated families with a previously uncharacterized complex axonal motor and sensory neuropathy accompanied by severe nonprogressive microcephaly and cerebral dysgenesis. Our data raise the question of whether VRK1 mutations disturb cell cycle progression and may result in apoptosis of cells in the nervous system. The application of unbiased genomic approaches allows the identification of potentially pathogenic mutations in unsuspected genes in highly genetically heterogeneous and uncharacterized neurological diseases.

}, keywords = {Child, Child, Preschool, DNA Mutational Analysis, Female, Genotype, Hereditary Sensory and Motor Neuropathy, Humans, Infant, Intracellular Signaling Peptides and Proteins, Magnetic Resonance Imaging, Male, Microcephaly, Mutation, Neural Conduction, Polymorphism, Single Nucleotide, Protein-Serine-Threonine Kinases}, issn = {2168-6157}, doi = {10.1001/jamaneurol.2013.4598}, author = {Gonzaga-Jauregui, Claudia and Lotze, Timothy and Jamal, Leila and Penney, Samantha and Campbell, Ian M and Pehlivan, Davut and Hunter, Jill V and Woodbury, Suzanne L and Raymond, Gerald and Adesina, Adekunle M and Jhangiani, Shalini N and Reid, Jeffrey G and Muzny, Donna M and Boerwinkle, Eric and Lupski, James R and Gibbs, Richard A and Wiszniewski, Wojciech} }