@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 {532, title = {Rapid molecular diagnostics of severe primary immunodeficiency determined by using targeted next-generation sequencing.}, journal = {J Allergy Clin Immunol}, volume = {138}, year = {2016}, month = {2016 10}, pages = {1142-1151.e2}, abstract = {

BACKGROUND: Primary immunodeficiency diseases (PIDDs) are inherited disorders of the immune system. The most severe form, severe combined immunodeficiency (SCID), presents with profound deficiencies of T~cells, B~cells, or both at birth. If not treated promptly, affected patients usually do not live beyond infancy because of infections. Genetic heterogeneity of SCID frequently delays the diagnosis; a specific diagnosis is crucial for life-saving treatment and optimal management.

OBJECTIVE: We developed a next-generation sequencing (NGS)-based multigene-targeted panel for SCID and other severe PIDDs requiring rapid therapeutic actions in a clinical laboratory setting.

METHODS: The target gene capture/NGS assay provides an average read depth of approximately 1000{\texttimes}. The deep coverage facilitates simultaneous detection of single nucleotide variants and exonic copy number variants in one comprehensive assessment. Exons with insufficient coverage (<20{\texttimes} read depth) or high sequence homology (pseudogenes) are complemented by amplicon-based sequencing with specific primers to ensure 100\% coverage of all targeted regions.

RESULTS: Analysis of 20 patient samples with low T-cell receptor excision circle numbers on newborn screening or a positive family history or clinical suspicion of SCID or other severe PIDD identified deleterious mutations in 14 of them. Identified pathogenic variants included both single nucleotide variants and exonic copy number variants, such as hemizygous nonsense, frameshift, and missense changes in IL2RG; compound heterozygous changes in ATM, RAG1, and CIITA; homozygous changes in DCLRE1C and IL7R; and a heterozygous nonsense mutation in CHD7.

CONCLUSION: High-throughput deep sequencing analysis with complete clinical validation greatly increases the diagnostic yield of severe primary immunodeficiency. Establishing a molecular diagnosis enables early immune reconstitution through prompt therapeutic intervention and guides management for improved long-term quality of life.

}, keywords = {Adolescent, Child, Female, Genetic Variation, Humans, Male, Pathology, Molecular, Sequence Analysis, DNA, Severe Combined Immunodeficiency}, issn = {1097-6825}, doi = {10.1016/j.jaci.2016.05.035}, author = {Yu, Hui and Zhang, Victor Wei and Stray-Pedersen, Asbj{\o}rg and Hanson, Imelda Celine and Forbes, Lisa R and de la Morena, M Teresa and Chinn, Ivan K and Gorman, Elizabeth and Mendelsohn, Nancy J and Pozos, Tamara and Wiszniewski, Wojciech and Nicholas, Sarah K and Yates, Anne B and Moore, Lindsey E and Berge, Knut Erik and Sorte, Hanne and Bayer, Diana K and ALZahrani, Daifulah and Geha, Raif S and Feng, Yanming and Wang, Guoli and Orange, Jordan S and Lupski, James R and Wang, Jing and Wong, Lee-Jun} } @article {297, title = {TM4SF20 ancestral deletion and susceptibility to a pediatric disorder of early language delay and cerebral white matter hyperintensities.}, journal = {Am J Hum Genet}, volume = {93}, year = {2013}, month = {2013 Aug 08}, pages = {197-210}, abstract = {

White matter hyperintensities (WMHs) of the brain are important markers of aging and small-vessel disease. WMHs are rare in healthy children and, when observed, often occur with comorbid neuroinflammatory or vasculitic processes. Here, we describe a complex 4 kb deletion in 2q36.3 that segregates with early childhood communication disorders and WMH in 15 unrelated families predominantly from Southeast Asia. The premature brain aging phenotype with punctate and multifocal WMHs was observed in ~70\% of young carrier parents who underwent brain MRI. The complex deletion removes the penultimate exon 3 of TM4SF20, a gene encoding a transmembrane protein of unknown function. Minigene analysis showed that the resultant net loss of an exon introduces a premature stop codon, which, in turn, leads to the generation of a stable protein that fails to target to the plasma membrane and accumulates in the cytoplasm. Finally, we report this deletion to be enriched in individuals of Vietnamese Kinh descent, with an allele frequency of about 1\%, embedded in an ancestral haplotype. Our data point to a constellation of early language delay and WMH phenotypes, driven by a likely toxic mechanism of TM4SF20 truncation, and highlight the importance of understanding and managing population-specific low-frequency pathogenic alleles.

}, keywords = {Age of Onset, Aging, Premature, Asian Continental Ancestry Group, Base Sequence, Brain, Child, Child, Preschool, Chromosomes, Human, Pair 2, Exons, Female, Genetic Predisposition to Disease, Humans, Language Development Disorders, Leukoencephalopathies, Magnetic Resonance Imaging, Male, Molecular Sequence Data, Pedigree, Sequence Analysis, DNA, Sequence Deletion, Tetraspanins}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.05.027}, author = {Wiszniewski, Wojciech and Hunter, Jill V and Hanchard, Neil A and Willer, Jason R and Shaw, Chad and Tian, Qi and Illner, Anna and Wang, Xueqing and Cheung, Sau W and Patel, Ankita and Campbell, Ian M and Gelowani, Violet and Hixson, Patricia and Ester, Audrey R and Azamian, Mahshid S and Potocki, Lorraine and Zapata, Gladys and Hernandez, Patricia P and Ramocki, Melissa B and Santos-Cortez, Regie L P and Wang, Gao and York, Michele K and Justice, Monica J and Chu, Zili D and Bader, Patricia I and Omo-Griffith, Lisa and Madduri, Nirupama S and Scharer, Gunter and Crawford, Heather P and Yanatatsaneejit, Pattamawadee and Eifert, Anna and Kerr, Jeffery and Bacino, Carlos A and Franklin, Adiaha I A and Goin-Kochel, Robin P and Simpson, Gayle and Immken, LaDonna and Haque, Muhammad E and Stosic, Marija and Williams, Misti D and Morgan, Thomas M and Pruthi, Sumit and Omary, Reed and Boyadjiev, Simeon A and Win, Kay K and Thida, Aye and Hurles, Matthew and Hibberd, Martin Lloyd and Khor, Chiea Chuen and Van Vinh Chau, Nguyen and Gallagher, Thomas E and Mutirangura, Apiwat and Stankiewicz, Pawel and Beaudet, Arthur L and Maletic-Savatic, Mirjana and Rosenfeld, Jill A and Shaffer, Lisa G and Davis, Erica E and Belmont, John W and Dunstan, Sarah and Simmons, Cameron P and Bonnen, Penelope E and Leal, Suzanne M and Katsanis, Nicholas and Lupski, James R and Lalani, Seema R} }