Definition, Etiology, PathogenesisTop
Medullary cystic kidney disease (MCKD) is an autosomal dominant genetic kidney disease. It is usually diagnosed in adults, sometimes in advanced age. Cysts and tubulointerstitial fibrosis develop due to an abnormal structure of the tubular basement membrane. Both kidneys are small. Cysts are also small and confined to the renal medulla. Some patients develop gout, which often appears as early as in adolescence; such individuals will usually have MCKD type II (also termed familial juvenile hyperuricemic nephropathy). In most such cases, a mutation in UMOD, the uromodulin gene that encodes for Tamm-Horsfall mucoprotein, will be found on chromosome 16. A minority of such patients have mutations in the renin gene (REN). Conversely, individuals with MCKD type I do not typically have early-onset gout but do have progressive interstitial kidney disease, which has recently been shown to be secondary to a mutation in the mucin-1 gene (MUC1).
Treatment is aimed at slowing down the progression of chronic kidney disease. Patients are usually not hypertensive and may in fact be hypotensive. End-stage renal failure requiring renal replacement therapy typically develops in individuals between the ages of 30 and 70 years.