Autosomal Dominant Tubulointerstitial Kidney Disease Due to MUC1 Mutation.

Mucin 1 kidney disease, previously referred to as medullary cystic kidney disease type 1, is a rare hereditary kidney disease. It is one of several diseases now termed autosomal dominant tubulointerstitial kidney disease, as proposed by a KDIGO (Kidney Disease: Improving Global Outcomes) consensus report in 2014. Autosomal dominant tubulointerstitial kidney diseases share common clinical findings, such as autosomal dominant inheritance, bland urinary sediment, absent to mild proteinuria, and progressive loss of kidney function. Although the pathophysiology of mucin 1 kidney disease is still under investigation, genetic testing has been developed to detect the most well-known mutation, a single cytosine insertion into a string of 7 cytosines in the variable-number tandem repeat (VNTR) region of the MUC-1 gene. With this diagnostic tool, nephrologists can offer genetic counseling to affected families and monitor closely for progression of disease. We report a Hispanic patient with a strong family history of chronic kidney disease who tested positive for the MUC1 mutation.