Objective: In last decades prevalence of type 2 diabetes mellitus (DM) in children and young people worldwide has been reported increase. It is necessary to know according to biochemical and genetic characteristics the frequency of DM no corresponding to type 1 in our population. The objective of this study was to determine the prevalence of mutations on hepatic nuclear factor 1 [alpha], and 4 [alpha] in diabetic patients younger than 35 years old with features of clinical autosomal dominant inheritance.
Material and Methods: The study included 140 diabetic patients (85 children and 55 young adults). It was approved by the local Ethical Committee. Glucose, C peptide, and β-cell autoantibodies measurements were performed. Polymorphisms of HNF [1 alpha] (I27L, G319S), and HNF [4 alpha] (T130I) were determined in all patients, when one of the polymorphisms was identified in a patient, all his/her family was studied by genetic evaluation.
Results: More than 50% patients showed overweight or obesity. The presence of DM in the father, overweight, and C peptide levels were higher in adults, while obesity, hypercholesterolemia, and β-cell autoantibodies were more frequent in those patients younger than 18 years old. Forty one (29.2%) patients showed the I27L polymorphism (24-Ile27Leu and 17-Leu27Leu). These patients were older, had higher BMI and C peptide levels than Ile27Ile patients, and only 3 of them showed β-cell autoantibodies. In 5 patients we identified Thr130Ile, and in one Gly319Ser polymorphisms. I27L mutation was present in 30 families and T130I in one family. Patients in these families were older and showed higher BMI and C peptide levels, but lower glucose levels.
Conclusion: I27L polymorphism was present in almost a third part of diabetic patients with clinical autosomal dominant inheritance of the disease. These patients showed clinical and biochemical characteristics of DM no corresponding to Type 1 DM.