@article {39, title = {Exome sequencing in mostly consanguineous Arab families with neurologic disease provides a high potential molecular diagnosis rate.}, journal = {BMC Med Genomics}, volume = {9}, year = {2016}, month = {2016 Jul 19}, pages = {42}, abstract = {

BACKGROUND: Neurodevelopment is orchestrated by a wide range of genes, and the genetic causes of neurodevelopmental disorders are thus heterogeneous. We applied whole exome sequencing (WES) for molecular diagnosis and in silico analysis to identify novel disease gene candidates in a cohort from Saudi Arabia with primarily Mendelian neurologic diseases.

METHODS: We performed WES in 31 mostly consanguineous Arab families and analyzed both single nucleotide and copy number variants (CNVs) from WES data. Interaction/expression network and pathway analyses, as well as paralog studies were utilized to investigate potential pathogenicity and disease association of novel candidate genes. Additional cases for candidate genes were identified through the clinical WES database at Baylor Miraca Genetics Laboratories and GeneMatcher.

RESULTS: We found known pathogenic or novel variants in known disease genes with phenotypic expansion in 6 families, disease-associated CNVs in 2 families, and 12 novel disease gene candidates in 11 families, including KIF5B, GRM7, FOXP4, MLLT1, and KDM2B. Overall, a potential molecular diagnosis was provided by variants in known disease genes in 17 families (54.8~\%) and by novel candidate disease genes in an additional 11 families, making the potential molecular diagnostic rate ~90~\%.

CONCLUSIONS: Molecular diagnostic rate from WES is improved by exome-predicted CNVs. Novel candidate disease gene discovery is facilitated by paralog studies and through the use of informatics tools and available databases to identify additional evidence for pathogenicity.

TRIAL REGISTRATION: Not applicable.

}, keywords = {Arabs, Cohort Studies, Consanguinity, Data Mining, Databases, Genetic, DNA Copy Number Variations, Exome, Female, High-Throughput Nucleotide Sequencing, Humans, Male, Molecular Diagnostic Techniques, Nervous System Diseases, Pedigree, Phenotype, Polymorphism, Single Nucleotide, Sequence Analysis, DNA}, issn = {1755-8794}, doi = {10.1186/s12920-016-0208-3}, author = {Charng, Wu-Lin and Karaca, Ender and Coban Akdemir, Zeynep and Gambin, Tomasz and Atik, Mehmed M and Gu, Shen and Posey, Jennifer E and Jhangiani, Shalini N and Muzny, Donna M and Doddapaneni, Harsha and Hu, Jianhong and Boerwinkle, Eric and Gibbs, Richard A and Rosenfeld, Jill A and Cui, Hong and Xia, Fan and Manickam, Kandamurugu and Yang, Yaping and Faqeih, Eissa A and Al Asmari, Ali and Saleh, Mohammed A M and El-Hattab, Ayman W and Lupski, James R} } @article {119, title = {Mechanisms for the Generation of Two Quadruplications Associated with Split-Hand Malformation.}, journal = {Hum Mutat}, volume = {37}, year = {2016}, month = {2016 Feb}, pages = {160-4}, abstract = {

Germline copy-number variants (CNVs) involving quadruplications are rare and the mechanisms generating them are largely unknown. Previously, we reported a 20-week gestation fetus with split-hand malformation; clinical microarray detected two maternally inherited triplications separated by a copy-number neutral region at 17p13.3, involving BHLHA9 and part of YWHAE. Here, we describe an 18-month-old male sibling of the previously described fetus with split-hand malformation. Custom high-density microarray and digital droplet PCR revealed the copy-number gains were actually quadruplications in the mother, the fetus, and her later born son. This quadruplication-normal-quadruplication pattern was shown to be expanded from the triplication-normal-triplication CNV at the same loci in the maternal grandmother. We mapped two breakpoint junctions and demonstrated that both are mediated by Alu repetitive elements and identical in these four individuals. We propose a three-step process combining Alu-mediated replicative-repair-based mechanism(s) and intergenerational, intrachromosomal nonallelic homologous recombination to generate the quadruplications in this family.

}, keywords = {14-3-3 Proteins, Adult, Aged, Alu Elements, Base Sequence, Basic Helix-Loop-Helix Transcription Factors, Chromosome Duplication, Chromosomes, Human, Pair 17, DNA Copy Number Variations, Female, Genetic Loci, Genome, Human, Hand Deformities, Congenital, Humans, Infant, Male, Molecular Sequence Data, Pedigree, Sequence Alignment, Sequence Analysis, DNA}, issn = {1098-1004}, doi = {10.1002/humu.22929}, author = {Gu, Shen and Posey, Jennifer E and Yuan, Bo and Carvalho, Claudia M B and Luk, H M and Erikson, Kelly and Lo, Ivan F M and Leung, Gordon K C and Pickering, Curtis R and Chung, Brian H Y and Lupski, James R} } @article {115, title = {Whole-Exome Sequencing in Familial Parkinson Disease.}, journal = {JAMA Neurol}, volume = {73}, year = {2016}, month = {2016 Jan}, pages = {68-75}, abstract = {

IMPORTANCE: Parkinson disease (PD) is a progressive neurodegenerative disease for which susceptibility is linked to genetic and environmental risk factors.

OBJECTIVE: To identify genetic variants contributing to disease risk in familial PD.

DESIGN, SETTING, AND PARTICIPANTS: A 2-stage study design that included a discovery cohort of families with PD and a replication cohort of familial probands was used. In the discovery cohort, rare exonic variants that segregated in multiple affected individuals in a family and were predicted to be conserved or damaging were retained. Genes with retained variants were prioritized if expressed in the brain and located within PD-relevant pathways. Genes in which prioritized variants were observed in at least 4 families were selected as candidate genes for replication in the replication cohort. The setting was among individuals with familial PD enrolled from academic movement disorder specialty clinics across the United States. All participants had a family history of PD.

MAIN OUTCOMES AND MEASURES: Identification of genes containing rare, likely deleterious, genetic variants in individuals with familial PD using a 2-stage exome sequencing study design.

RESULTS: The 93 individuals from 32 families in the discovery cohort (49.5\% [46 of 93] female) had a mean (SD) age at onset of 61.8 (10.0) years. The 49 individuals with familial PD in the replication cohort (32.6\% [16 of 49] female) had a mean (SD) age at onset of 50.1 (15.7) years. Discovery cohort recruitment dates were 1999 to 2009, and replication cohort recruitment dates were 2003 to 2014. Data analysis dates were 2011 to 2015. Three genes containing a total of 13 rare and potentially damaging variants were prioritized in the discovery cohort. Two of these genes (TNK2 and TNR) also had rare variants that were predicted to be damaging in the replication cohort. All 9 variants identified in the 2 replicated genes in 12 families across the discovery and replication cohorts were confirmed via Sanger sequencing.

CONCLUSIONS AND RELEVANCE: TNK2 and TNR harbored rare, likely deleterious, variants in individuals having familial PD, with similar findings in an independent cohort. To our knowledge, these genes have not been previously associated with PD, although they have been linked to critical neuronal functions. Further studies are required to confirm a potential role for these genes in the pathogenesis of PD.

}, keywords = {Adult, Aged, Cohort Studies, Exome, Female, Genetic Predisposition to Disease, Genetic Variation, Humans, Male, Middle Aged, Parkinsonian Disorders, Protein-Tyrosine Kinases, Sequence Analysis, DNA, Tenascin}, issn = {2168-6157}, doi = {10.1001/jamaneurol.2015.3266}, author = {Farlow, Janice L and Robak, Laurie A and Hetrick, Kurt and Bowling, Kevin and Boerwinkle, Eric and Coban-Akdemir, Zeynep H and Gambin, Tomasz and Gibbs, Richard A and Gu, Shen and Jain, Preti and Jankovic, Joseph and Jhangiani, Shalini and Kaw, Kaveeta and Lai, Dongbing and Lin, Hai and Ling, Hua and Liu, Yunlong and Lupski, James R and Muzny, Donna and Porter, Paula and Pugh, Elizabeth and White, Janson and Doheny, Kimberly and Myers, Richard M and Shulman, Joshua M and Foroud, Tatiana} }