A Novel Heterozygous and Pathogenic Variant of the HNF1B Gene Associated with Autosomal Dominant Tubulointerstitial Kidney Disease with a Broad Spectrum of Extrarenal Phenotypes.

We encountered a family with hereditary renal failure, renal medullary cysts, pancreatic hypoplasia, hypomagnesemia, liver enzyme abnormalities, and diabetes mellitus (DM). We identified a novel heterozygous variant of HNF1B (NM_000458.4:c.791dup, p.L264Ffs*30) using whole-exome sequencing of genomic DNA samples from this family. This variant is located in the DNA-binding domain of the HNF1B protein and produces a truncated protein with a de novo sequence, suggesting that this variant changes HNF1B binding to genomic DNA or causes nonsense-mediated mRNA decay. Based on the phenotypes and identified gene variants, this family suffers from autosomal dominant tubulointerstitial kidney disease caused by this HNF1B variant.