Case Study: RDDC RNA Splicer Accurately Predicts GPI Splicing Variant Pathogenicity
The RDDC RNA Splicing Prediction Model (RNA Splicer) AI tool demonstrates key value in deciphering the pathogenic mechanisms of rare hereditary hemolytic anemias. In a study focused on a family with Glucose Phosphate Isomerase (GPI) deficiency, the tool successfully predicted the functional consequences of a novel variant at a non-canonical splice site in the GPI gene. RDDC's predictions (including exon skipping and intron retention) were subsequently precisely validated by a minigene assay, clarifying the variant's pathogenicity and providing a "prediction-validation" diagnostic paradigm for this rare anemia.
Research Challenge: WES Identifies a Non-Canonical Splice Site VUS
The challenge in this study originated from a 4-year-old boy presenting with persistent anemia, jaundice, and hepatosplenomegaly. Targeted capture sequencing identified compound heterozygous variants in his GPI gene: a known missense mutation, c.295G>T (p.G87C), and a novel intronic variant, c.633+3A>G, located in intron 7. This c.633+3A>G variant, positioned at a non-canonical splice site (+3), was not reported in public databases and qualified as a "Variant of Uncertain Significance" (VUS). To confirm the patient's diagnosis, it was essential to determine if this intronic variant was pathogenic and to understand its specific functional impact.
RDDC's Precise Prediction: Unveiling Complex Splicing Aberrations
To evaluate the potential impact of the c.633+3A>G variant before conducting functional experiments, the research team utilized RDDC's RNA Splicing Prediction Model AI tool. This advanced algorithm predicts splicing pattern alterations caused by variants. For this specific variant, RDDC's prediction was critical. It suggested the variant could activate a new donor site, leading to a 2bp insertion, and further predicted complex outcomes such as exon skipping or intron retention. This in silico prediction provided clear molecular hypotheses for subsequent wet-lab validation.
Experimental Validation: Minigene Results Align with RDDC's Prediction
The research team then performed an in vitro minigene assay to validate RDDC's predictions. The experimental results powerfully confirmed RDDC's accuracy: the construct carrying the c.633+3A>G mutation produced three transcripts: a normal transcript, a transcript lacking exons 5-7 (exon skipping), and a transcript with an intron insertion (intron retention). The observed aberrant splicing patterns were consistent with the RDDC RNA Splicer's predictions. This result confirmed that the c.633+3A>G variant causes mRNA degradation or protein dysfunction through abnormal splicing, which, in concert with the p.G87C missense mutation, leads to the patient's GPI deficiency and hemolytic anemia.
Case Implications
This case highlights the robust capability of RDDC RNA Splicer in deciphering the pathogenicity of VUS at non-canonical splice sites (like the +3 position). It provides precise, specific molecular mechanism predictions that effectively guide subsequent functional validation experiments, greatly enhancing diagnostic efficiency. This "RDDC prediction + functional experiment" pathway offers a valuable paradigm for the precise diagnosis and mechanistic study of GPI deficiency and other rare hereditary blood disorders.
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:
Yang W, Liu T, Liu J, et al. The novel compound heterozygous variants identified in a Chinese family with glucose phosphate isomerase deficiency and pathogenicity analysis. BMC Medical Genomics. 2023 Jul 11;16(1):153.
Article Link: https://pubmed.ncbi.nlm.nih.gov/37430284/
