Functional Characterization and Pathogenicity Classification of PRRT2 Splice Variants in PRRT2-Related Disorders

Area of Science:

• Genetics
• Neurology
• Molecular Biology

Background:

• Paroxysmal kinesigenic dyskinesia (PKD) is a common hereditary movement disorder.
• The PRRT2 gene is the primary genetic cause of PKD.
• Investigating PRRT2 splice region variants is crucial for understanding PKD pathogenesis.

Purpose of the Study:

• To determine the pathogenicity of PRRT2 variants in splice regions.
• To enhance the genetic diagnosis of paroxysmal kinesigenic dyskinesia.
• To evaluate the role of in silico and functional assays in variant classification.

Main Methods:

• Targeted next-generation sequencing of the PRRT2 gene.
• In silico analysis of splice region variants from patient cohorts and HGMD.
• Functional assays using a minigene system in HEK293T cells to assess splicing abnormalities.

Main Results:

• Fourteen PRRT2 variants were analyzed, including intronic, synonymous, deletion, and missense types.
• In silico predictions indicated potential splicing disruption for most variants.
• Functional assays confirmed aberrant splicing (exon skipping, intron retention) for 11 variants, enabling reclassification of five previously uncertain PRRT2 variants.

Conclusions:

• A combined approach of in silico analysis and functional assays is essential for accurate pathogenicity assessment of PRRT2 splice variants.
• This methodology improves the genetic diagnosis of paroxysmal kinesigenic dyskinesia and related disorders.
• Accurate variant classification aids in confirming diagnoses for patients with suspected PRRT2-related conditions.