ESPE Abstracts

Background: Mitochondrial disease is an uncommon cause of diabetes mellitus and hypoparathyroidism in children. Coexistence of these two endocrinopathies in a child with mitochondrial disease is extremely rare.

Case report: An 11-year-old girl was diagnosed with type 1 diabetes mellitus due to a blood glucose of 300 mg/dl. Simultaneous C-peptide and insulin were very low, however anti-GAD, anti-islet cell and anti-insulin antibodies were negative. HbA1c was 10.2% (N: 4.5–6.2%). Insulin was started, however repeated and frequent hypoglycemic episodes required replacing insulin with diabetic diet alone. HbA1c decreased to 5.4% on diabetic diet. At 12 years she developed paresthesias of the hands, and numbness around mouth during illness. Serum Ca level was 8.4 mg/dl (N: 9–11), P: 6.8 mg/dl (N: 3.7–5.4) ALP: 194 U/l (N: 105–420) and simultaneous PTH was 10.6 pg/mlml (N: 15–69) Low dose calcitriol treatment was started. At 13 years of age, she was referred to us for blood glucose regulation and insulin had to be reintroduced due to an increase in HbA1c to 8.4%. She was the second child of unrelated parents. Her grandmother had type 2 diabetes, and a maternal aunt had ptosis. On physical examination, height was 133.5 cm (<3 p) and BMI 12.2 kg/m² (<3 p).She had bilateral ptosis, external ophthalmoplegia, macular dystrophy, and sensorineural hearing loss at high frequencies. She had no weakness, and neurological examination was otherwise normal. Persistently high lactate combined with the clinical phenotype led to muscle biopsy showing ragged-blue fibers and cytochrome-c-oxidase negative fibers compatible with mitochondrial myopathy.

Conclusion: Diabetes mellitus accompanying hypoparathyroidism, is an expected finding in autoimmune polyglandular syndrome. This patient reminds that it may also be seen in mitochondrial disease, however rare. Thus one should consider mitochondrial disease in differential diagnosis of patients with multiple endocrine abnormalities even when weakness or myopathy is absent. Also complete endocrine evaluation should be part of mitochondrial disease.