Mutations in the hepatocyte nuclear factor-4α gene in maturity-onset diabetes of the young (MODY1)

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Abstract
THE disease maturity-onset diabetes of the young (MODY) is a genetically heterogeneous monogenic form of non-insulin-dependent (type 2) diabetes mellitus (NIDDM), characterized by early onset, usually before 25 years of age and often in adolescence or childhood, and by autosomal dominant inheritance1. It has been estimated that 2–5% of patients with NIDDM may have this form of diabetes mellitus2,3. Clinical studies have shown that predia-betic MODY subjects have normal insulin sensitivity but suffer from a defect in glucose-stimulated insulin secretion, suggesting that pancreatic β-cell dysfunction rather than insulin resistance is the primary defect in this disorder4,5. Linkage studies have localized the genes that are mutated in MODY on human chromosomes 20 (MODY1)6, 7 (MODY2)2 and 12 (MODY3}7, with MODY2 and MODY3 being allelic with the genes encoding glucokinase2, a key regulator of insulin secretion, and hepatocyte nuclear factor-1α (HNF-1α)8, a transcription factor involved in tissue-specific regulation of liver genes but also expressed in pancreatic islets, insulinoma cells and other tissues. Here we show that MODY1 is the gene encoding HNF-4α (gene symbol, TCP14), a member of the steroid/thyroid hormone receptor superfamily and an upstream regulator of HNF-1α expression9–11.