Heterozygous mutations in the genes encoding uromodulin (UMOD), [1] hepatocyte nuclear factor 1β (HNF1B), [2] renin (REN) [3] and mucin-1 (MUC1) [4] can result in autosomal dominant tubulointerstitial kidney disease (ADTKD). Here, MUC1 is linked to autosomal dominant medullary cystic kidney disease with or without hyperuricemia.