Progressive external ophthalmoplegia, autosomal dominant, type 5 (Q97287)

Autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions-5 (PEOA5) is caused by heterozygous mutation in the nuclear-encoded RRM2B gene (604712) on chromosome 8q23.1. Patients had progressive external ophthalmoplegia with variable additional features, including ptosis, fatigue, dysphagia, proximal myopathy, dysarthria, ataxia, gastrointestinal symptoms, and diabetes. Skeletal muscle biopsy shows a mosaic defect of Cytochrome c oxidase activity and multiple mitochondrial DNA deletions.