Autosomal Dominant Polycystic Kidney Disease (ADPKD) is caused by mutations in PKD1 or PKD2 genes, encoding polycystin-1 (PC1) or polycystin-2 (PC2), respectively, characterized by excessive cell proliferation and fluid secretion, resulting in renal cyst formation and growth. The gene discussed is PKD2; the disease is autosomal dominant polycystic kidney disease.