Autosomal dominant polycystic kidney disease (ADPKD), the most common congenital kidney disorder, is commonly accompanied by abnormal activity of JAK-STAT pathways.344,345 Forced STAT5 expression in ADPKD causes aberrant proliferation by transcriptionally upregulating cyclin D1 in a growth hormone-dependent manner. The gene discussed is STAT5A; the disease is autosomal dominant polycystic kidney disease.