RESUMO
OBJECTIVE: To describe the results of mutation analysis of the genes involved in maturity onset diabetes of the young (MODY) types 1-3. DESIGN: Descriptive. METHOD: In the period July 2000-October 2003 the DNA from 184 possible MODY patients was analysed for the presence of mutations of the genes involved in MODY types 1, 2 and 3. The patients fulfilled at least one of the following criteria: diabetes mellitus had been diagnosed before the age of 25, or at least before the age of 40, there was a family history of diabetes mellitus at an early age, there were no characteristics to indicate diabetes mellitus type 1 or 2. RESULTS: In the blood of 65 patients (35%) a pathogenic gene mutation was found. A total of 45 patients had a mutation in the HNF-1alpha-gene (which is linked to MODY3), 11 in the glucokinase gene (MODY2) and 9 in the HNF-4alpha-gene (MODY1). Of all the HNF-1alpha-gene mutations, the insertion of a C in codon 291 was the most frequently seen (in 11 families). A mutation in exon 9 of the HNF-1alpha-gene was also shown in 9 apparently non-related families, which probably was a founder mutation. CONCLUSION: The MODY subtype was found in one third of the selected patients. This diagnosis may have implications in the clinical management of the patient.