[MODY 3 correlations between the genotype and clinical manifestations of diabetes]

We analyzed the mutations identified in a family affected by Maturity-Onset Diabetes of the Young (MODY3), and searched for correlations between the genotype and clinical manifestations of diabetes. In 4 of 9 subjects we have demonstrated a heterozygous missense mutation in hepatocyte nuclear factor 1 alfa (HNF1α). The missense mutation, caused by a G>A transition at nucleotide 815 of exon 4 (c.815G>A), resulted in the substitution of arginine with histidine at codon 272 (p.Arg272His). This mutation occurs in the DNA binding domain of HNF1α. Heterogenity of clinical characteristic in patients was evident. Variability in age of onset, presence of obesity and evolution time was present. In conclusion, clinical presentation of diabetes is otherwise atipical for the assumed etiology. Thus, the diagnosis of MODY should be raised in various clinical circumstances. Molecular diagnosis has important consequences in terms of prognosis, family screening, and therapy.