Cysts only involve a portion of nephron, so renal function is maintained until 40's to 50's.
Relatively common, seen in 1 of 400-1,000 live births and responsible for 5-10% of CRF requiring dialysis.
Autosomal dominant; most common cystic renal disease and most common genetically transmitted disease (1:500 - 1:1000)
25% has no family history.
Caused by mutations in genes at chr 16p13.3 (PKD1) that encodes for polycystin-1 and at chr 4q21 (PKD2) that encodes for polycystin-2.
PKD1 is more common (85%) and associated with more severe disease and earlier onset (30's).
Presents with hypertension, renal failure and abdominal pain.
Extrarenal involvement: Liver cysts (90%), cyst in pancreas (10%), seminal vesicles, pineal glands, and mitral valve prolase.
Gross: kidneys are massively enlarged and multicystic with essentially complete replacement of renal cortex (image A) & (image B). Hint: kidney larger and cyst more widespread than in acquired cystic disease (related to dialysis) because patients in the later have shrunken kidneys of CRF before acquiring cysts.
Cystic dilatation of terminal ends of ampullary collecting ducts, proximal convoluted tubules, and Bowman's capsule (glomerular or tubular cysts) (image C).
Cysts can be up to several centimeters.
Cysts lined by a single layer of cuboidal or flattened cells.
Complications: Metanephric abscesses; hypertension; berry aneurysms of Circle of Willis; nephrolithiasis; and RCC (1-5% of cases).
CRF beginning at age 40-60 years.
~1/2 requires dialysis by age 50.