[A familial case of proliferative diabetic retinopathy associated with a mutation in the mitochondrial gene]

We report a 39-year-old male patient with proliferative diabetic retinopathy associated with a mutation in the mitochondrial DNA and with his family. The patient was referred for fundus examination in 1993. He had been diagnosed as having diabetes mellitus 15 years before but his diabetic control was not good. He was thin and short and presented with bilateral proliferative diabetic retinopathy. When he received pan retinal photocoagulation, an exudative retinal detachment was found in his left eye, but it disappeared spontaneously. The patient's history included sensorineural deafness and autonomic nerve system disorder. Mitochondrial analysis obtained from blood showed mutation of adenine to guanine at mitochondrial DNA 3243. Generally speaking, mitochondrial disorders often include pigmentary degeneration. For this reason diabetic patients with mitochondrial disorders rarely suffer proliferative diabetic retinopathy. In this case, the retinitis pigmentosa was not so severe as to cause the proliferative change, so that it was probably derived from heteroplasmy.