Morphological Findings of Extraocular Myopathy with Chronic Progressive External Ophthalmoplegia

Abstract

Mitochondrial diseases are a large group of disorders resulting from mutations of nuclear DNA (nDNA) and mitochondrial DNA (mtDNA). Patients present clinically with multiple manifestations, including myopathies and multiple system disorders. Establishing a specific diagnosis often requires extensive clinical and laboratory evaluation. In this study of 2 adult patients with presumptive mitochondrial disease, the authors have identified distinctive morphological changes in medial rectus muscle biopsies that confirm the diagnosis of chronic progressive external ophthalmoplegia (CPEO). These findings demonstrate the usefulness of electron microscopy using medial rectus muscle in the diagnosis of adult patients with a slowly progressive course of mild skeletal weakness and CPEO.

Keywords:

• CPEO
• mitochondria
• ultrastructure

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Notes

The authors are thankful to Ina Lomakina for her technical support.