@article {698, title = {Paralog Studies Augment Gene Discovery: DDX and DHX Genes.}, journal = {Am J Hum Genet}, volume = {105}, year = {2019}, month = {2019 Aug 01}, pages = {302-316}, abstract = {

Members of a paralogous gene family in which variation in one gene is known to cause disease are eight times more likely to also be associated with human disease. Recent studies have elucidated DHX30 and DDX3X as genes for which pathogenic variant alleles are involved in neurodevelopmental disorders. We hypothesized that variants in paralogous genes encoding members of the DExD/H-box RNA helicase superfamily might also underlie developmental delay and/or intellectual disability (DD and/or ID) disease phenotypes. Here we describe 15 unrelated individuals who have DD and/or ID, central nervous system (CNS) dysfunction, vertebral anomalies, and dysmorphic features and were found to have probably damaging variants in DExD/H-box RNA helicase genes. In addition, these individuals exhibit a variety of other tissue and organ system involvement including ocular, outer ear, hearing, cardiac, and kidney tissues. Five individuals with homozygous (one), compound-heterozygous (two), or de novo (two) missense variants in DHX37 were identified by exome sequencing. We identified ten total individuals with missense variants in three other DDX/DHX paralogs: DHX16 (four~individuals), DDX54 (three individuals), and DHX34 (three individuals). Most identified variants are rare, predicted to be damaging, and occur at conserved amino acid residues. Taken together, these 15 individuals implicate the DExD/H-box helicases in both dominantly and recessively inherited neurodevelopmental phenotypes and highlight the potential for more than one disease mechanism underlying these disorders.

}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.06.001}, author = {Paine, Ingrid and Posey, Jennifer E and Grochowski, Christopher M and Jhangiani, Shalini N and Rosenheck, Sarah and Kleyner, Robert and Marmorale, Taylor and Yoon, Margaret and Wang, Kai and Robison, Reid and Cappuccio, Gerarda and Pinelli, Michele and Magli, Adriano and Coban Akdemir, Zeynep and Hui, Joannie and Yeung, Wai Lan and Wong, Bibiana K Y and Ortega, Lucia and Bekheirnia, Mir Reza and Bierhals, Tatjana and Hempel, Maja and Johannsen, Jessika and Santer, Ren{\'e} and Aktas, Dilek and Alika{\c s}ifo{\u g}lu, Mehmet and Bozdogan, Sevcan and Aydin, Hatip and Karaca, Ender and Bayram, Yavuz and Ityel, Hadas and Dorschner, Michael and White, Janson J and Wilichowski, Ekkehard and Wortmann, Saskia B and Casella, Erasmo B and Kitajima, Joao Paulo and Kok, Fernando and Monteiro, Fabiola and Muzny, Donna M and Bamshad, Michael and Gibbs, Richard A and Sutton, V Reid and Van Esch, Hilde and Brunetti-Pierri, Nicola and Hildebrandt, Friedhelm and Brautbar, Ariel and Van den Veyver, Ignatia B and Glass, Ian and Lessel, Davor and Lyon, Gholson J and Lupski, James R} } @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} }