@article {357, title = {Lessons learned from additional research analyses of unsolved clinical exome cases.}, journal = {Genome Med}, volume = {9}, year = {2017}, month = {2017 03 21}, pages = {26}, abstract = {

BACKGROUND: Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery.

METHODS: We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols.

RESULTS: Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36\% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51\% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6\%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6\%), 1/1 multiplex family involving three affected siblings, and 3/4 (75\%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3).

CONCLUSION: An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.

}, keywords = {Adenosine Triphosphatases, ATPases Associated with Diverse Cellular Activities, Computational Biology, DNA Copy Number Variations, DNA-Binding Proteins, Exome, Female, Genetic Diseases, Inborn, Genomics, GTP-Binding Protein beta Subunits, Humans, Male, Membrane Proteins, Metalloendopeptidases, Mitochondrial Proteins, Pilot Projects, Polymorphism, Single Nucleotide, Sequence Analysis, DNA, Transcription Factors}, issn = {1756-994X}, doi = {10.1186/s13073-017-0412-6}, author = {Eldomery, Mohammad K and Coban-Akdemir, Zeynep and Harel, Tamar and Rosenfeld, Jill A and Gambin, Tomasz and Stray-Pedersen, Asbj{\o}rg and K{\"u}ry, S{\'e}bastien and Mercier, Sandra and Lessel, Davor and Denecke, Jonas and Wiszniewski, Wojciech and Penney, Samantha and Liu, Pengfei and Bi, Weimin and Lalani, Seema R and Schaaf, Christian P and Wangler, Michael F and Bacino, Carlos A and Lewis, Richard Alan and Potocki, Lorraine and Graham, Brett H and Belmont, John W and Scaglia, Fernando and Orange, Jordan S and Jhangiani, Shalini N and Chiang, Theodore and Doddapaneni, Harsha and Hu, Jianhong and Muzny, Donna M and Xia, Fan and Beaudet, Arthur L and Boerwinkle, Eric and Eng, Christine M and Plon, Sharon E and Sutton, V Reid and Gibbs, Richard A and Posey, Jennifer E and Yang, Yaping and Lupski, James R} } @article {65, title = {Germline De Novo Mutations in GNB1 Cause Severe Neurodevelopmental Disability, Hypotonia, and Seizures.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 05 05}, pages = {1001-1010}, abstract = {

Whole-exome sequencing of 13 individuals with developmental delay commonly accompanied by abnormal muscle tone and seizures identified de novo missense mutations enriched within a sub-region of GNB1, a gene encoding the guanine nucleotide-binding protein~subunit beta-1, Gβ. These 13 individuals were identified among a base of 5,855 individuals recruited for various undiagnosed genetic disorders. The probability of observing 13 or more de novo mutations by chance among 5,855 individuals is very low (p~=~7.1~{\texttimes} 10(-21)), implicating GNB1 as a genome-wide-significant disease-associated gene. The majority of these 13 mutations affect known Gβ binding sites, which suggests that a likely disease mechanism is through the disruption of the protein interface required for Gα-Gβγ interaction (resulting in a constitutively active Gβγ) or through the disruption of residues relevant for interaction between Gβγ and certain downstream effectors (resulting in reduced interaction with the effectors). Strikingly, 8 of the 13 individuals recruited here for a neurodevelopmental disorder have a germline de novo GNB1 mutation that overlaps a set of five recurrent somatic tumor mutations for which recent functional studies demonstrated a gain-of-function effect due to constitutive activation of G protein downstream signaling cascades for some of the affected residues.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Developmental Disabilities, Exome, Female, Germ-Line Mutation, GTP-Binding Protein beta Subunits, Humans, Infant, Intellectual Disability, Male, Muscle Hypotonia, Phenotype, Protein Conformation, Seizures, Signal Transduction, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.03.011}, author = {Petrovski, Slav{\'e} and K{\"u}ry, S{\'e}bastien and Myers, Candace T and Anyane-Yeboa, Kwame and Cogn{\'e}, Benjamin and Bialer, Martin and Xia, Fan and Hemati, Parisa and Riviello, James and Mehaffey, Michele and Besnard, Thomas and Becraft, Emily and Wadley, Alexandrea and Politi, Anya Revah and Colombo, Sophie and Zhu, Xiaolin and Ren, Zhong and Andrews, Ian and Dudding-Byth, Tracy and Schneider, Amy L and Wallace, Geoffrey and Rosen, Aaron B I and Schelley, Susan and Enns, Gregory M and Corre, Pierre and Dalton, Joline and Mercier, Sandra and Latypova, X{\'e}nia and Schmitt, S{\'e}bastien and Guzman, Edwin and Moore, Christine and Bier, Louise and Heinzen, Erin L and Karachunski, Peter and Shur, Natasha and Grebe, Theresa and Basinger, Alice and Nguyen, Joanne M and B{\'e}zieau, St{\'e}phane and Wierenga, Klaas and Bernstein, Jonathan A and Scheffer, Ingrid E and Rosenfeld, Jill A and Mefford, Heather C and Isidor, Bertrand and Goldstein, David B} }