1. Long-read DNA and cDNA sequencing identify cancer-predisposing deep intronic variation in tumor-suppressor genes.
- Author
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Gulsuner S, AbuRayyan A, Mandell JB, Lee MK, Bernier GV, Norquist BM, Pierce SB, King MC, and Walsh T
- Subjects
- Humans, Female, Male, Genes, Tumor Suppressor, DNA, Complementary genetics, Genetic Predisposition to Disease, Neoplasms genetics, Sequence Analysis, DNA methods, BRCA1 Protein genetics, Fanconi Anemia Complementation Group N Protein genetics, Tumor Suppressor Proteins genetics, Ataxia Telangiectasia Mutated Proteins genetics, Breast Neoplasms genetics, Genetic Variation, Introns
- Abstract
The vast majority of deeply intronic genomic variants are benign, but some extremely rare or private deep intronic variants lead to exonification of intronic sequence with abnormal transcriptional consequences. Damaging variants of this class are likely underreported as causes of disease for several reasons: Most clinical DNA and RNA testing does not include full intronic sequences; many of these variants lie in complex repetitive regions that cannot be aligned from short-read whole-genome sequence; and, until recently, consequences of deep intronic variants were not accurately predicted by in silico tools. We evaluated the frequency and consequences of rare deep intronic variants for families severely affected with breast, ovarian, pancreatic, and/or metastatic prostate cancer, but with no causal variant identified by any previous genomic or cDNA-based approach. For 10 tumor-suppressor genes, we used multiplexed adaptive sampling long-read DNA sequencing and cDNA sequencing, based on patient-derived DNA and RNA, to systematically evaluate deep intronic variation. We identified all variants across the full genomic loci of targeted genes, applied the in silico tools SpliceAI and Pangolin to predict variants of functional consequence, and then carried out long-read cDNA sequencing to identify aberrant transcripts. For eight of the 120 (6%) previously unsolved families, rare deep intronic variants in BRCA1 , PALB2 , and ATM create intronic pseudoexons that are spliced into transcripts, leading to premature truncations. These results suggest that long-read DNA and cDNA sequencing can be integrated into variant discovery, with strategies for accurately characterizing pathogenic variants., (© 2024 Gulsuner et al.; Published by Cold Spring Harbor Laboratory Press.)
- Published
- 2024
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