Ocular histopathologic study of a patient with the T 8993-G point mutation in Leigh's syndrome.

Abstract Objective To report the histopathologic findings of eyes from a patient with Leigh's syndrome associated with the T 8993-G point mutation in mitochondrial DNA (mtDNA). Design Case report. Intervention A child with hypotonia, developmental delay, persistent lactic acidosis, seizures, and ataxia died of aspiration pneumonia at 15 months of age. Analysis of DNA isolated from blood was positive for the T to G point mutation at position 8993 in mtDNA, and the proportion of mutant genomes was estimated at approximately 95%. The type and distribution of abnormalities seen in the brain at autopsy were consistent with those in patients with Leigh's syndrome. Main outcome measures The left eye was examined by light microscopy, and segments of the right eye were examined by transmission electron microscopy. Genetic analysis on DNA isolated from blood was performed. Results Thinning of the nerve fiber and ganglion cell layers was present in the nasal aspect of the macula, and mild atrophy of the temporal aspect of the optic nerve head and optic nerve was present. Electron microscopic study disclosed numerous distended mitochondria in all cells, but particularly in the retinal pigment epithelium, nonpigmented ciliary epithelium, and corneal endothelium. Conclusion This is a report of the ocular histopathologic findings in Leigh's syndrome with the T 8993-G point mutation. The light microscopic findings were similar to those of patients with similar features reported previously. In addition, ultrastructural abnormalities of mitochondria were present.