ESPE Abstracts

Introduction: Diabetes mellitus can develop as a result different etiology. Mitochondrial diseases may also cause diabetes mellitus. However, mitochondrial mutations are generally thought to be accompanied by a severe clinical finding. We present a patient who is determined 80% heteroplasmic deletion in the MT-DNT1 gene, with hearing loss and mitochondrial diabetes, which is quite different from the classical phenotype.

Case: A 10-year-old male patient, who was diagnosed with diabetes mellitus in another medical center 6 months ago, was started on insulin therapy and applied to our outpatient clinic for follow-up. In his history; He was born 3700 grams as a term birth by spontaneous vaginal delivery, was operated at the age of 1 due to an undescended testis. When he was ten months old, he started using a hearing device. In his development assessment, he started walking at the age of 15 months, and his language development was later than that of his peers. In the family history; there was a 3-degree cousin marriage between his parents, the father was diagnosed as type 2 diabetes. The mother had not any type of diabetes mellitus. Anthropometric measurements; his height, weight and body mass index were 159 cm (SDS:2,25), 58,1 kg (SDS:2,053) and 23 kg/m2 (1,63 SDS) respectively. In his examination; he had hearing aid. Testicular volume was 3 ml on the right, left testis was non-palpable. Neurologic and other systemic examinations were normal. Laboratory examinations revealed; hemogram, kidney and liver function tests, vitamin and mineral levels, thyroid function tests and tissue transglutaminase antibodies were normal. HbA1C: 10.9, C peptide 0.6 (1.1-4.4 g/L), anti-GAD: 10.91 IU/ml (0-17IU/ml), anti-insulin antibody 6.95U/ ml (<20 U/ml), Islet Cell Antibody: 23.56U/ml (0-28 U/ml). As diabetes autoantibodies were negative, genetic analyzes were performed in the patient who also accompanied by hearing loss. Heteroplasmic deletion was detected in 80% of the patient's MT-DNT1 gene. The patient whose genetics were compatible with MELAS syndrome was accepted as mitochondrial diabetes. Other parameters of MELAS mutation were examined, lactic acid level was normal. The patient's EMG was normal, and there was no finding in favor of stroke in the cranial imaging. Genetic studies of the family members were normal.

Conclusions: Mitochondrial disorders should be kept in mind in diabetic patients with hearing loss and negative result of autoantibody, and genetic studies should be performed. In this way, early intervention will be possible for other accompanying system disorders.