What is medullary cystic kidney disease (MCKD)?
Autosomal dominant tubulointerstitial kidney disease, also known as MCKD, is a new term that has been proposed for a group of diseases with an autosomal dominant pattern of inheritance, characterized by small to normal size kidneys, cysts primarily located at the corticomedullary junction, associated with irregular thickening of the tubular basement membrane, tubular atrophy, and interstitial fibrosis. The disease is caused by mutations in at least four genes: MUC1 (chromosome 1q22) encoding mucin-1, UMOD (chromosome 16p12.3) encoding uromodulin, HNF1β (chromosome 17q12) encoding hepatocyte nuclear factor-1b, REN (chromosome 1q32.1) encoding renin.
Clinical presenting symptoms include polydipsia and polyuria, low-grade proteinuria, benign urine sediment, and subsequent development of CKD. These patients are commonly diagnosed and develop ESKD at a later age compared with those with nephronophthisis (NPHP). In addition, MCKD patients do not have extrarenal involvement, with the exception of gout. A history of gout at an early age or a strong family history of gout is suggestive of mutations in UMOD , whereas a history of anemia in childhood and mildly elevated serum potassium concentrations is suggestive of mutations in REN . If none of the preceding clinical characteristics is present, MUC1 molecular genetic testing should be considered.
Kidney transplantation is the preferred treatment for MCKD-induced ESKD. Exhaustive diagnostic evaluation should be performed in living related donors.
