Identification of Novel Pathogenic PKD2 Variants in Iranian Patients with Autosomal Dominant Polycystic Kidney Disease

Background: Autosomal dominant polycystic kidney disease (ADPKD) is a delayed-onset renal disorder that results from a mutation in the PKD1 or PKD2 genes. Autosomal dominant polycystic kidney disease results in end-stage renal disease due to renal cystic dysplasia. The aim of this study was to evaluate, by exon sequencing, the disease-causing variants of PKD2 (exons 4, 6, and 8) in Iranian ADPKD patients.

Methods: Genomic DNA was extracted from 3-5 ml of peripheral blood by the salting-out method. PKD2 exons 4, 6, and 8 were PCR-amplified and sequenced.

Results: Three disease-causing PKD2 variants were identified; all three were missense mutations in exon 4. The mutations were AGC → ACC (c.893G>C, cDNA.959G>C, S298T), TAC → TTC (c.1043A>T, cDNA.1109 A>T, Y348F), and GAA → GAT (c.1059A>T, cDNA.1125 A>T, E353D. These novel pathogenic variants may cause loss of the normal protein function.

Conclusion: Our results suggest that AGC → ACC (c.893G>C, cDNA.959G>C, S298T), TAC → TTC (c.1043A>T, cDNA.1109 A>T, Y348F), and GAA → GAT (c.1059A>T, cDNA.1125 A>T, E353D variants are common in Iranian ADPKD patients. These mutations modify the transmembrane domain and likely influence PC2 function.