Buccal Swab Analysis of Mitochondrial Enzyme Deficiency and DNA Defects in a Child With Suspected Myoclonic Epilepsy and Ragged Red Fibers (MERRF)

The authors describe mitochondrial studies in a 6-year-old patient with a seizure disorder that can be seen in myoclonic epilepsy and ragged red fibers. Using a recently developed noninvasive approach, analysis of buccal mitochondrial enzyme function revealed severe respiratory complex I and IV deficiencies in the patient. In addition, analysis of buccal mitochondrial DNA showed significant amounts of the common 5 kb and 7.4 kb mitochondrial DNA deletions, also detectable in blood. This study suggests that a buccal swab approach can be used to informatively examine mitochondrial dysfunction in children with seizures and may be applicable to screening mitochondrial disease with other clinical presentations.