Effect of high-dose vitamins, coenzyme Q and high-fat diet in paediatric patients with mitochondrial diseases.

We reviewed the medical records of all patients with confirmed mitochondrial diseases treated with any or all of thiamin, riboflavin, coenzyme Q, vitamin C (approximately 10 mg/kg per day) and a high-fat diet (50-60% of caloric intake) between 1997 and 2003. There were 15 patients (9 male): 10 had enzymatic deficiency and 10 had a molecular diagnosis. Age at diagnosis was 11 months to 17 years 10 months. Treatment was commenced at time of clinical diagnosis in 12 patients. Follow-up period was 3 days to 7 years (median 22 months). Improvement was reported in 9 patients, of whom 4 attained further developmental skills, but this was only temporary in 6 patients. Five patients died during the follow-up period (3 days to 7 years). Patients with the 3243A > G mutation showed no significant change in the course of their disease, except for fewer migraine attacks. Of the six patients who had seizures, one has had a significant reduction in the severity of the seizures and one has had no further seizures. Plasma lactate levels were noncontributory. We conclude that high-dose vitamin and cofactor treatment and, where applicable, high-fat diet, are well tolerated and possibly effective in the short term, but ineffective in the longer term.