Gene Discovery

Hunting for New Therapies

There is a treasure trove of valuable information in both the mapped and unmapped reads of the genome.

Gene Discovery involves identifying novel genes implicated in causing rare disease, developing methods to identify patient’s predisposition to a rare disease and building the knowledge base to improve clinical management of novel genetic disease.

At RCIGM, this work is led by Matthew Bainbridge, PhD, Assistant Director of Translational Research. His team develops novel analysis techniques to squeeze every last bit of information from WGS and to attempt to identify uncommon disease mechanisms (such as ALU insertions and deep intronic mutations) in the pediatric patient population. 

Bioinformatic analysis of Whole Genome Sequencing (WGS) data is used to gain a better understanding of the mechanisms by which pathogenic genomic variants contribute to the development of rare diseases.

Traditional wet-lab modeling of novel diseases is used to functionalize variants of uncertain significance.

Research Projects

Several grant funded research projects are currently under Dr. Bainbridge’s direction:

  • Oligogenic Models of Cardiomyopathy
    The goal is to identify synergistic and modifier mutations that impact structural cardiomyopathies.  Bioinformatically identified variants are prioritized and then functionally tested by Dr. Neil Chi at UC San Diego. Learn More

Matthew Bainbridge, PhD

RCIGM Assistant Director of Translational Research

Publications

Madelyn A Gillentine

Genome Med. 2021 Apr 19;13(1):63. doi: 10.1186/s13073-021-00870-6.

ABSTRACT

BACKGROUND: With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations.

METHODS: We tested our hypothesis by considering gene families that have multiple members with an enrichment of de novo variants among NDDs, as determined by previous meta-analyses. One of these gene families is the heterogeneous nuclear ribonucleoproteins (hnRNPs), which has 33 members, five of which have been recently identified as NDD genes (HNRNPK, HNRNPU, HNRNPH1, HNRNPH2, and HNRNPR) and two of which have significant enrichment in our previous meta-analysis of probands with NDDs (HNRNPU and SYNCRIP). Utilizing protein homology, mutation analyses, gene expression analyses, and phenotypic characterization, we provide evidence for variation in 12 HNRNP genes as candidates for NDDs. Seven are potentially novel while the remaining genes in the family likely do not significantly contribute to NDD risk.

RESULTS: We report 119 new NDD cases (64 de novo variants) through sequencing and international collaborations and combined with published clinical case reports. We consider 235 cases with gene-disruptive single-nucleotide variants or indels and 15 cases with small copy number variants. Three hnRNP-encoding genes reach nominal or exome-wide significance for de novo variant enrichment, while nine are candidates for pathogenic mutations. Comparison of HNRNP gene expression shows a pattern consistent with a role in cerebral cortical development with enriched expression among radial glial progenitors. Clinical assessment of probands (n = 188-221) expands the phenotypes associated with HNRNP rare variants, and phenotypes associated with variation in the HNRNP genes distinguishes them as a subgroup of NDDs.

CONCLUSIONS: Overall, our novel approach of exploiting gene families in NDDs identifies new HNRNP-related disorders, expands the phenotypes of known HNRNP-related disorders, strongly implicates disruption of the hnRNPs as a whole in NDDs, and supports that NDD subtypes likely have shared molecular pathogenesis. To date, this is the first study to identify novel genetic disorders based on the presence of disorders in related genes. We also perform the first phenotypic analyses focusing on related genes. Finally, we show that radial glial expression of these genes is likely critical during neurodevelopment. This is important for diagnostics, as well as developing strategies to best study these genes for the development of therapeutics.

PMID:33874999   DOI:10.1186/s13073-021-00870-6

Sci Rep. 2020 Jul 3;10(1):11020. doi: 10.1038/s41598-020-67656-5.

ABSTRACT

Rapid whole genome sequencing (rWGS) of peripheral blood has been used to detect microbial DNA in acute infections. Cytomegalovirus (CMV) is a herpesvirus capable of causing severe disease in neonates and immunocompromised patients. We identified CMV in patients undergoing diagnostic rWGS by matching reads that did not align to the human reference genome to a database of microbial genomes. rWGS was conducted on peripheral blood obtained from ill pediatric patients (age 1 day to 18 years). Reads not aligning to the human genome were analyzed using an in-house pipeline to identify DNA consistent with CMV infection. Of 669 patients who received rWGS from July 2016 through July 2019, we identified 28 patients (4.2%) with reads that aligned to the CMV reference genome. Six of these patients had clinical findings consistent with symptomatic CMV infection. Positive results were highly correlated (R2 > 0.99, p < 0.001) to a CMV-qPCR assay conducted on DNA isolated from whole blood samples. In acutely ill children receiving rWGS for diagnosis of genetic disease, we propose analysis of patient genetic data to identify CMV, which could impact treatment of up to 4% of children in the intensive care unit.

PMID:32620939 | PMC:PMC7335102 | DOI:10.1038/s41598-020-67656-5

Elucidating the molecular pathogenesis of glioma: integrated germline and somatic profiling of a familial glioma case series.

Neuro Oncol. 2018 Nov 12;20(12):1625-1633. doi: 10.1093/neuonc/noy119. PMID: 30165405; PMCID: PMC6231201.

Abstract

Key points: 1. Familial and sporadic gliomas display highly comparable molecular landscapes. 2. Germline and somatic molecular events target common core pathways involved in gliomagenesis. 3. Carriage of germline glioma risk variants is not associated with somatic events in the same gene.

PMID: 30165405 | PMCID: PMC6231201 | DOI: 10.1093/neuonc/noy119

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