HNF1B and autosomal dominant medullary cystic kidney disease with or without hyperuricemia: Heterozygote mutations in the encoding gene lead to autosomal dominant tubulointerstitial kidney disease–HNF1B,2 and besides cystic kidney disease the clinical spectrum can include renal malformations, diabetes, genital tract abnormalities, exocrine pancreatic insufficency, and gout.3, 4 The high clinical variability, a spontaneous mutation rate of approximately 50%, and variable penetrance hamper clinical diagnosis.5