Unusual findings in Leigh syndrome caused by T8993C mutation.

The pathological nature of Leigh syndrome is highly variable and depends on the underlying mitochondrial or nuclear genome defect. Mitochondrial m.8993T>G and m.8993T>C mutations are responsible for both NARP (neurogenic weakness, ataxia and retinitis pigmentosa) and Leigh syndrome depending on the amount of mutant mtDNA. The clinical findings of Leigh syndrome caused by the m.8993T>C mutation are less severe than those associated with the m.8993T>G mutation, and ragged red fibers, oligoclonal bands in cerebrospinal fluid, and additional deficiencies of respiratory enzyme complexes are usually not found. This report presents a two year old girl with Leigh syndrome caused by a m.8993T>C mutation. Interestingly she had ragged red fibers in muscle tissue, oligoclonal bands in CSF and focal deficient histochemical staining for complexes I and IV.