Background: Heterozygous truncating variants cause 10% to 20% of idiopathic dilated cardiomyopathy (DCM). Although variants which disrupt canonical splice signals (ie, invariant dinucleotide of the splice donor site, invariant dinucleotide of the splice acceptor site) at exon-intron junctions are readily recognized as truncating variants, the effects of other nearby sequence variations on splicing and their contribution to disease is uncertain.
Methods: Rare variants of unknown significance located in the splice regions of highly expressed exons from 203 DCM cases, 3329 normal subjects, and clinical variant databases were identified. The effects of these variants on splicing were assessed using an in vitro splice assay.
Results: Splice-altering variants of unknown significance were enriched in DCM cases over controls and present in 2% of DCM patients (=0.002). Application of this method to clinical variant databases demonstrated 20% of similar variants of unknown significance in splice regions affect splicing. Noncanonical splice-altering variants were most frequently located at position +5 of the donor site (=4.4×10) and position -3 of the acceptor site (=0.002). SpliceAI, an emerging in silico prediction tool, had a high positive predictive value (86%-95%) but poor sensitivity (15%-50%) for the detection of splice-altering variants. Alternate exons spliced out of most transcripts frequently lacked the consensus base at +5 donor and -3 acceptor positions.
Conclusions: Noncanonical splice-altering variants in explain 1-2% of DCM and offer a 10-20% increase in the diagnostic power of sequencing in this disease. These data suggest rules that may improve efforts to detect splice-altering variants in other genes and may explain the low percent splicing observed for many alternate exons.
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http://dx.doi.org/10.1161/CIRCGEN.121.003389 | DOI Listing |
Mutations that impact splicing play a significant role in disease etiology but are not fully understood. To characterize the impact of exonic variants on splicing in 71 clinically-actionable disease genes in asymptomatic people, we analyzed 32,112 exonic mutations from ClinVar and Geisinger MyCode using a minigene reporter assay. We identify 1,733 splice-disrupting mutations, of which the most extreme 1-2% of variants are likely to be deleterious.
View Article and Find Full Text PDFJ Med Genet
December 2024
Revvity Omics, Waltham, Massachusetts, USA
Background: Pathogenic variants in the gene are associated with dystrophinopathy including Duchenne and Becker muscular dystrophy (DMD/BMD). Targeted gene, gene panels, exomes and genome sequencing have advanced genetic diagnostics, yet some cases remain elusive.
Methods: We performed total RNA sequencing (RNAseq) on muscle biopsy from 13 male patients with a clinical diagnosis of DMD/BMD.
Neuromuscul Disord
December 2024
Department of Neurology, Children's Hospital of Fudan University, Shanghai, PR China. Electronic address:
Duchenne muscular dystrophy (DMD) is a genetic disorder characterized by progressive muscle degeneration and weakness, due to mutations in the DMD gene, which encodes the dystrophin protein. While mutations within the coding regions of DMD have been extensively studied, recent focus has shifted to deep intronic variants for their potential impact on disease severity. Here, we characterize two deep intronic variants, c.
View Article and Find Full Text PDFNat Commun
September 2024
Vanderbilt Center for Arrhythmia Research and Therapeutics (VanCART), Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
Interpreting the clinical significance of putative splice-altering variants outside canonical splice sites remains difficult without time-intensive experimental studies. To address this, we introduce Parallel Splice Effect Sequencing (ParSE-seq), a multiplexed assay to quantify variant effects on RNA splicing. We first apply this technique to study hundreds of variants in the arrhythmia-associated gene SCN5A.
View Article and Find Full Text PDFSci Transl Med
September 2024
Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
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