This 41 year old man has been diabetic since age 14. He has also had difficulty with hearing since age 8 and the hearing loss progressed to a cochlear implant at age 22. At age 40 he experienced reduced cognition and ataxia and was diagnosed with Parkinson's disease. Most recently he has developed end-stage renal disease. His mother has ptosis in one eye, which was corrected with surgery, His half-sister had early onset diabetes, proliferative diabetic retinopathy and end stage renal disease.

The clinical features favoring the diagnosis of Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) in this patient include foveal-sparing geographic atrophy, diabetes mellitus, deafness, external ophthalmoplegia, ptosis, muscle weakness, renal failure and impaired cognition.