A 25-Year-Old Woman with Droopy Eyelids and Double Vision

Mitochondrial myopathy is caused by mutations in nuclear or mitochondrial genes with resultant defects in the mitochondrial oxidative phosphorylation function. Patients with mitochondrial myopathy usually present with chronic progressive bilateral eyelid ptosis and ophthalmoplegia. They may also manifest fixed proximal limb weakness, cardiac conduction block, cardiomyopathy, hearing loss, retinopathy, and diabetes mellitus, among others. Here we present a case of mitochondrial myopathy with clinical, pathological, and genetic features consistent with Kearns-Sayre syndrome.