Polycystic kidney disease

What it is

In autosomal dominant polycystic kidney disease numerous cysts form in the cortex and the medulla, the kidneys become bilaterally enlarged, and the cysts ultimately destroy the kidney parenchyma. It is one of the two named causes of enlarged kidneys, with diabetic nephropathy, and the enlargement is massive because the cysts are numerous. The mutation is in PKD1, which accounts for 85% of cases and sits on chromosome 16, or in PKD2, which accounts for 15% and sits on chromosome 4.

The recessive form is different. There is cystic dilation of the collecting ducts, it often presents in infancy, and it is associated with congenital hepatic fibrosis.

The adult form is autosomal dominant with full penetrance, and it is worth holding beside it the conditions that share that pattern: neurofibromatosis type 1, tuberous sclerosis, hereditary spherocytosis, Marfans syndrome and osteogenesis imperfecta share the same inheritance. Put as one line, it is an autosomal dominant bilateral disease whose signs and symptoms begin in early or middle adult life with hematuria, nephrolithiasis and uremia; 33% of cases have cysts in liver, 10% to 20% of patients have intracranial aneurysms, and HTN is present in 70% of patients at diagnosis. The juvenile version is autosomal recessive and much rarer than the adult type, and almost all of those patients have cysts in liver and portal bile duct proliferation, which is the congenital hepatic fibrosis.