Divergent phenotypes in siblings with identical novel mutations in the HNF-1α gene leading to maturity onset diabetes of the young type 3.

Background: Maturity onset diabetes of the young (MODY) is an autosomal dominant form of non-insulin-dependent diabetes mellitus caused by mutations in at least 13 different genes. The hepatocyte nuclear factor (HNF)-1α gene is affected in the most common form (HNF1A-MODY [MODY3]).

Case Presentation: We describe the co-inheritance of a novel heterozygous missense mutation c.