Diabètes mitochondriaux

Among all cases of mitochondrial diabetes due to mutations or deletion of mitochondrial DNA, Maternally Inherited Diabetes and Deafness (MIDD), which results from a point mutation 3243 A >G, is the most frequently observed form. Described on 1992, MIDD is characterized by its matrilineal inheritance, and its particular phenotype: early onset, low BMI, short stature (in male patients), and associated extrapancreatic manifestations (neurosensorial deafness, pattern dystrophy, neurological and muscular manifestations, cardiomyopathy). Clinically, diabetes presents as either type 1 or type 2 diabetes (80% of cases). It is related to a primary defect in insulin secretion, due to mitochondrial respiratory chain dysfunction. Diabetic retinopathy is less frequent than in common forms of diabetes, due to a less severe hyperglycaemia, and to a lower prevalence of hypertension. A specific mitochondrial nephropathy with poor prognosis is observed in MIDD patients. Coenzyme Q10 should be proposed as curative and preventive treatment. Molecular diagnosis is usually performed from circulating leucocytes. Around 20 different mutations or deletions of mitochondrial DNA associated with diabetes have been described.