An inherited disorder that causes a gradual loss of kidney function, caused by a mutation in the MUC1 gene that leads to production of an abnormal mucin 1 protein, which deposits in the kidney and leads to slow loss of kidney function. The disease is tubulointerstitial kidney disease, autosomal dominant, 2 (MONDO_0020726). Also known as: ADTKD-MUC1, MCKD1, MUC1-related autosomal dominant medullary cystic kidney disease, MUCI-related ADTKD, autosomal dominant medullary cystic kidney disease without hyperuricemia, autosomal dominant tubulointerstitial kidney disease due to mutations in MUC1, medullary cystic kidney disease 1, medullary cystic kidney disease type 1.