Medullary Cystic Kidney Disease Type I (Experimental Factor Ontology term EFO_0008617) is an inherited form of cystic kidney disease that leads to fibrosis and impaired renal function as a result of defects in the MUC1 gene, which encodes mucin 1. [ NICHD NCI ]. Also known as: Autosomal Dominant Interstitial Kidney Disease.