2017 Volume 60 Issue 2 Pages 91-97
A 28-year-old woman first experienced muscle cramps in both lower legs from April 2006 and developed diabetic ketosis 1 month later, with a low insulin secretory level and positive anti-GAD antibody test results. She was diagnosed with type 1 diabetes mellitus and treated with multiple daily insulin injections. Her muscle cramps did not resolve thereafter, and because she frequently experienced painful episodes complicated with muscle destruction, she was hospitalized in 2012 for further scrutiny. She had a short stature, emaciation, a maternal family history of diabetes mellitus, sensorineural hearing loss, high lactate levels in both blood and cerebrospinal fluid, calcification of the basal ganglia of brain and an A3243G mutation in the mitochondrial DNA-encoded tRNA (Leu,UUR) gene. Her major neurological and muscular symptoms were restricted to muscle cramps and mild sensory disturbance, and the duration from the onset of diabetes mellitus was very short; her symptoms were therefore considered to be associated with mitochondrial gene abnormalities rather than diabetic polyneuropathy. Mitochondrial diabetes may be associated with a decreased insulin secretory capacity and therefore treated as type 1 diabetes mellitus, but there is less involvement of autoimmune mechanisms and positive anti-GAD antibody test results are rare.
