Introduction: Point mutation at position 3243 (A>G) of the mitochondrial DNA is associated with diabetes mellitus manifested in young adulthood, which has a progressive nature. The defect of the first phase of insulin secretion followed by insulinopenia is in the background of the progressive impairment of glucose tolerance. Insulin resistance is not a characteristic feature. Sensorineural hearing loss, myopathy, ataxia, epilepsy, stroke like episodes, cardiomyopathy can associate with the diabetes. The inheritance of the disease is exclusively maternally. The name of the syndrome in the Anglo-Saxon literature is maternally inherited diabetes and deafness (MIDD). The glucose intolerance can be manifested clinically as either type 1 or type 2 diabetes. Aim: The authors analyse the first two Hungarian MIDD families. Methods: Beside the clinical examination and the identification of the mitochondrial gene mutation they made HLA-typing, frequently sampled intravenous glucose tolerance test and islet cell autoantibody determination. Results: The A3243G heteroplasmy value varied between 5 and 30 %. No family member was found who carried HLA haplotype with high risk for type 1 diabetes mellitus. A missing first phase and a decreased total C-peptid response was detected in the mutation positive diabetics compared with controls. Grculating islet cell cytoplasmic antibody was present in three patients with MIDD. GADA and 1A2A were missing. Conclusions: A missing first phase and a decreased total C-peptid response during an IVGTT was characteristic for the A3243G mutation. The development of islet cell antibodies can be a secondary phenomenon induced by the destruction of islet cells caused by the energy insufficiency associated with the impairement of mitochondrial function. The proper dignosis of MIDD can be made based on the maternal inheritance of diabetes and familial occurrence of hearing loss. The diagnosis is important, as metformin is contraindicated in this type of diabetes.
|Number of pages||7|
|Publication status||Published - Dec 1 2010|
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