Mitochondrial Diabetes: More Than Just Hyperglycemia.

Abstract

Juvenile-onset diabetes is often branded as type 1 diabetes when a clear family history is absent. A high degree of suspicion regarding other forms of diabetes should be kept in mind when systems not known to be affected by hyperglycemia or associated with type 1 diabetes are involved. Such a scenario is often complicated by the slow evolution of symptomatology and the absence of diabetes in family members. Here, we report on a genetically proven mitochondrial A3243G mutation–related syndromic diabetes in a young patient whose mitochondrial disease–related multisystem symptomatology slowly evolved over the course of a decade. Our association with the patient started from his childhood (Figure 1). His first visit to our hospital was for short stature at the age of 9 years. Systemic work-up and growth hormone studies were normal. Familial factors were thought to be responsible. He was noted to have an IQ of 75, with poor performance in school. FIGURE 1. Chronology of symptoms in the patient. At the age of 16 years, he presented to us with diabetes without ketosis or a family history of diabetes. Tests for GAD65 and IA2 antibodies were negative at this stage. Although a trial of oral hypoglycemic agents was instituted, he was soon shifted to insulin therapy because of his poor response. Two years later, he presented with gastrointestinal symptoms in the form of intermittent diarrhea. Work-up for celiac disease and pancreatic insufficiency, including upper and lower endoscopies with biopsies, was normal. Fortunately, the diarrhea subsided, which was attributed by the family to dietary manipulation, especially restriction of wheat products. At around this time, sensorineural hearing loss was documented. The combination of these symptoms led to a consideration of mitochondrial diabetes. However, fundus evaluation for characteristic pigmentary changes was normal. Also around this …