De novo PKD1 splicing and missense variants in two familial ADPKD: Molecular characterization and genetic counseling implications.

This study identifies two pedigrees with autosomal dominant polycystic kidney disease (ADPKD) caused by de novo PKD1 variants. Proband A carried a heterozygous splicing variant (c.9202-16G > A), presenting with bilateral renal cysts. The miniGENE assay confirmed this variant causes aberrant splicing with a 60-base excision, leading to a frameshift and a predicted truncated protein. Proband B carried a missense variant (c.2180 T > C; p.Leu727Pro), presenting with polycystic kidney and liver disease. Structural modeling revealed this variant severely disrupts local secondary structure and a critical spatial interaction, compromising protein stability. Functional analyses demonstrate that both de novo variants are pathogenic through distinct mechanisms, implicating aberrant splicing and structural disruption in ADPKD etiology.