Case Overview
RDDC's RNA Splicing Prediction Model (RNA Splicer) AI bioinformatics tool has once again demonstrated its critical value in deciphering the pathogenic mechanisms of rare hereditary blood disorders. In a study focused on a pediatric patient with Hereditary Spherocytosis (HS), the tool successfully predicted the functional consequences of a novel de novo variant located at a canonical splice site in the SPTB gene. RDDC's predictions (exon skipping/deletion) were highly consistent with subsequent minigene assay results, not only accurately elucidating the variant's pathogenic mechanism but also providing decisive evidence for the patient's HS diagnosis and ACMG pathogenicity classification.
Research Challenge: Identifying a de novo Splice Site VUS in a Rare HS Case
This study centered on a 7-year-old boy diagnosed with HS due to recurrent anemia, jaundice, characteristic spherocytes, and abnormal osmotic fragility. Lacking a family history, the research team performed targeted sequencing on the patient and his parents to identify the genetic cause. This revealed a novel heterozygous variant in the patient's SPTB gene: c.301–2A>G, located at the canonical splice acceptor site of intron 2. Sanger sequencing confirmed this as a de novo mutation, absent in both parents. Although situated at a critical, highly conserved splice site, the specific molecular consequences of this "Variant of Uncertain Significance" (VUS) required bioinformatic prediction and functional validation for accurate pathogenicity assessment.
RDDC's Precise Prediction: Unveiling Key Aberrant Splicing Patterns
To evaluate the potential pathogenic mechanism of the c.301–2A>G VUS, researchers employed RDDC's RNA Splicing Prediction Model AI bioinformatics tool, alongside SpliceAI and HSF. RDDC's prediction provided clear and specific molecular hypotheses, indicating the variant could lead to two main aberrant splicing outcomes:
Predicted Aberrant Splicing Patterns
- A 6 bp deletion associated with the generation of a new acceptor site
- Skipping of exon 3 (a 174 bp deletion)
Both predictions strongly suggested the variant would cause a frameshift and introduce a premature termination codon, ultimately leading to a truncated, loss-of-function β-spectrin protein (encoded by SPTB), thereby destabilizing the red blood cell membrane.
Experimental Validation: Confirming RDDC's Accuracy
The research team promptly validated RDDC's predictions using an in vitro minigene assay. After transfecting HEK293T cells with plasmids carrying the mutation, RT-PCR and sequencing revealed three major aberrant transcripts (r.301_474del, r.301_306delCCAAAG, r.301-1_301-57ins). The experimentally observed aberrant splicing patterns were highly consistent with the molecular consequences (exon skipping/internal deletion leading to protein truncation) predicted by RDDC.
ACMG Pathogenicity Classification
The perfect concordance between the in silico prediction and the in vitro validation provided strong evidence for the pathogenicity of the c.301–2A>G variant. Combined with its de novo status and predicted loss-of-function effect, the variant was successfully classified as "Pathogenic" (PVS1+PS2+PM2) according to ACMG guidelines.
Case Implications
This case highlights the powerful capability and clinical utility of RDDC RNA Splicer in interpreting splice site VUS. It provides precise, specific predictions of molecular mechanisms (like exon skipping, base deletions), effectively guides subsequent functional validation experiments, and offers critical evidence for ACMG pathogenicity classification. This "RDDC prediction + functional experiment + ACMG classification" pathway provides a valuable paradigm for the precise diagnosis, mechanistic research, and genetic counseling of Hereditary Spherocytosis and other rare genetic disorders.
Clinical Significance
This case demonstrates the important role of AI bioinformatics tools in rare disease diagnosis, particularly when dealing with complex genetic variants such as splice site mutations. RDDC RNA Splicer can provide accurate functional predictions, significantly improving diagnostic efficiency and accuracy.
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
Wang Y, Liu T, Jia C, et al. A novel variant in the SPTB gene underlying hereditary spherocytosis and a literature review of previous variants. BMC Medical Genomics. 2024 Feb 23;17(1):51.
Article Link: https://pubmed.ncbi.nlm.nih.gov/39135028/
