Polycystic Kidney Disease (PKD)

Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts in the kidneys. It is one of the most common hereditary kidney diseases, affecting approximately 1 in 400 to 1 in 1,000 people worldwide. There are two main forms: autosomal dominant PKD (ADPKD), which typically manifests in adulthood and is the more common form, and autosomal recessive PKD (ARPKD), which presents in infancy or childhood and is much rarer. PKD is the fourth leading cause of end-stage renal disease (ESRD) in the United States. ADPKD is caused by mutations in the PKD1 (chromosome 16) or PKD2 (chromosome 4) genes, which encode proteins polycystin-1 and polycystin-2. These proteins are involved in the regulation of cell growth and differentiation in the kidney tubules. Mutations lead to abnormal cell proliferation and fluid secretion, resulting in the formation and progressive enlargement of cysts. The cysts replace normal kidney tissue, gradually impairing kidney function. By age 60, approximately 50% of ADPKD patients require dialysis or transplantation. PKD also affects other organs, including the liver (hepatic cysts), pancreas, and brain (increased risk of intracranial aneurysms). Management of PKD focuses on slowing the progression of kidney disease, managing symptoms, and preventing complications. Tolvaptan (Jynarque) is a newer FDA-approved medication that has been shown to slow the growth of kidney cysts and delay the decline in kidney function in ADPKD patients. Blood pressure control, adequate hydration, and a low-sodium diet are essential components of management. Regular monitoring of kidney function, blood pressure, and screening for complications (liver cysts, intracranial aneurysms) is important. Genetic counseling is recommended for affected families. Eventually, most ADPKD patients will require dialysis or kidney transplantation.