TRPV4 function and its role in Ca+2 regulation were evaluated in ADPKD human kidneys and normal regions of human kidneys collected from nephrectomy specimens that were removed to treat renal carcinomas or withheld from transplantation, which were referred to as normal human kidneys (NHKs). The gene discussed is TRPV4; the disease is autosomal dominant polycystic kidney disease.