Case Study: RDDC RNA Splicer Accurately Predicts Pathogenic Mechanism of Novel RS1 Splicing Variant
In the research of rare inherited retinal diseases, accurately assessing novel variants, especially those at splice sites, is crucial for uncovering pathogenic mechanisms and guiding diagnosis. A recent study involving a Chinese twin family with Congenital Retinoschisis highlights the key role of the RDDC RNA Splicer Tool (SpliceTool) in this process. In this study, RDDC provided a precise prediction for a novel splice site mutation in the RS1 gene, which was consistent with subsequent experimental validation, successfully elucidating the variant's pathogenic mechanism.
Research Challenge: Determining Function of a Novel Splice Site VUS
The study involved a Chinese family where twin brothers and their father were diagnosed with congenital retinoschisis, exhibiting typical foveal "spoke-wheel" patterns and inner nuclear layer schisis cavities. Whole Exome Sequencing (WES) identified a novel hemizygous mutation in these patients at the canonical splice acceptor site of intron 1 in the RS1 gene: c.53-1G>A.
This variant was absent from public databases, classifying it as a "Variant of Uncertain Significance" (VUS). Determining whether it was the cause of the family's disease required clarifying its specific impact on RS1 mRNA splicing.
RDDC's Precise Prediction: Unveiling Two Aberrant Splicing Modes
To assess the functional consequences of this VUS before investing in experimental resources, the research team utilized RDDC's RNA Splicer Tool (SpliceTool) among other bioinformatics tools. RDDC's analysis provided critical, testable hypotheses regarding the pathogenic mechanism, predicting that the c.53-1G>A variant would lead to two main aberrant splicing events:
Aberrant Splicing Patterns
- Insertion of 29 bp from intron 1: The variant was predicted to cause partial retention of the intronic sequence in the mature mRNA.
- Deletion of 26 bp from exon 1: Alternatively, the variant was predicted to cause skipping of a portion of exon 1.
RDDC's prediction clearly indicated that both aberrant splicing modes would result in a frameshift and premature protein termination. This would lead to a truncated, non-functional RS1 protein, impairing its role in cell adhesion.
Clinical Significance: RDDC Prediction Guides Diagnosis and Counseling
The study mentions that RDDC's prediction was consistent with subsequent experimental validation results. This strongly confirmed the pathogenicity of the novel c.53-1G>A splicing mutation. This case demonstrates the powerful capability of RDDC RNA Splicer in functionally analyzing splice site VUS.
Research Value
By providing precise molecular mechanism predictions, RDDC not only helped researchers confirm the pathogenic variant but also offered crucial scientific support for early genetic diagnosis, female carrier screening, and genetic counseling for this disease, showcasing the value of the "bioinformatics prediction followed by experimental validation" pathway in rare disease research.
Content Source and Disclaimer
This article is a compilation and interpretation of the scientific study cited below, intended to highlight the application of RDDC bioinformatics tools. All research data and conclusions belong to the original authors and publication.
Original Article
Song W, Zhang Y, Zhang Y, et al. Novel mutation in RS1 and clinical manifestations in a Chinese twin family with congenital retinoschisis. Ophthalmic Genetics. 2022 Dec;43(6):804-811.
Article Link: https://pubmed.ncbi.nlm.nih.gov/36212125/
