PROJECT SUMMARY/ABSTRACT The genetic basis of >2,920 Mendelian conditions (MCs) remains unknown, and hundreds of novel MCs are described each year. Our group has, in partnership with 2,379 investigators from 656 institutions in 55 countries, assessed 15,387 samples from 5,675 families and has, over the past decade, identified genes for 1379 MCs, including 915 novel discoveries. The translation and impact of these discoveries on diagnostics and clinical care has been immediate and substantial. Additionally, we have developed multiple new analytical tools including CADD, PRIMUS, CoNIFER, SMRT-SV, RV-TDT, as well as methodological innovations including MIPs, smMIPs, and approaches for low input exome and genome sequencing (ES/WGS). We are also deeply committed to open data sharing with rolling submission of exome and genome data to the AnVIL (1,439 deposited); development of a MatchMaker Exchange node (http://MyGene2.org) that enables public sharing of genotype and phenotypic data among families, researchers, and clinicians; and creation of a public data browser (http://geno2mp.gs.washington.edu) that links de-identified, individual-level genotypes from over 18,000 exomes/genomes to individual phenotypes. In this application, we build upon these successes to establish the University of Washington Mendelian Genomics Research Center (UW-MGRC) with the overarching goal to maximize novel gene discovery for MCs, with an emphasis on canonical MCs that have gone unsolved using ES/WGS, and noncoding variants underlying MCs. To this end, we will develop novel approaches to inform variant interpretation and functional validation for the human genetics community at-large and disseminate results, data, and tools openly. We will capitalize on immediate access to sequence-ready samples from ~300 MCs (>26,000 samples), 1,500 samples suspected of harboring a causal noncoding variant for a MC, and an aggressive sample solicitation plan in partnership with industry, academic centers, and other NIH programs. We propose three specific aims: (1) maximize novel gene discovery for MCs by solicitation, sequencing, and analysis of families with unexplained (i.e., no known underlying gene) MCs; classic MCs considered high priority by the clinical genetics community and that have been recalcitrant to gene discovery efforts; and cases that remain unsolved after prior exome or genome sequencing. (2) Develop new strategies for gene discovery for unsolved MCs caused by variants that are difficult to detect or of unknown functional effects (e.g., structural variants, repeat expansions, cryptic splice, regulatory, etc.), and/or unusual modes of inheritance, and, in doing so, characterize the genetic architecture of pathogenic noncoding variants underlying MCs. Implement high- throughput screening and targeted follow-up functional studies to prioritize and validate assertions of pathogenicity of candidate noncoding variants. (3) Take a leadership role to openly and publicly, when feasible, share sequencing and rich phenotypic metadata, methods, and knowledge, to empower investigators worldwide and accelerate the pace of gene discovery.

PROJECT NARRATIVE Mendelian conditions, which include diseases, but also include phenotypic differences that may not be considered a “disease,” are caused mainly by mutations in the protein-coding regions of the genome. Although the genes underlying thousands of Mendelian phenotypes have been identified, there are thousands of Mendelian conditions for which the gene(s) remain to be discovered. We propose to use an extensive network of clinicians and investigators, next generation sequencing coupled with new analytical paradigms, and technological innovations to efficiently discover novel genes for as many Mendelian conditions as possible.