Unilateral multicystic dysplastic kidney is the form of multicystic dysplastic kidney (MCDK), a congenital anomaly of the kidney and urinary tract (CAKUT), in which one kidney is large, distended by multiple cysts, and non-functional. The disease is unilateral multicystic dysplastic kidney (Monarch Disease Ontology id MONDO_0019981). Also known as: unilateral MCDK, unilateral multicystic renal dysplasia.