In many patients mitochondrial disease leads to progressive nerve and muscle damage that may be associated with problems with thinking, talking, remembering, walking or balancing. Sometimes it may also cause abnormal build up in the blood and spinal fluid of a substance called lactic acid. This problem makes the blood and spinal fluid too acid, which can be life-threatening. There is no known specific or effective treatment for mitochondrial diseases. Sometimes certain diets can improve the condition but seldom prevent the nerve or muscle damage or reduce the chance of developing life-threatening acidity of the blood.

CoQ10 is not approved by the Food and Drug Administration (FDA) for the treatment of mitochondrial diseases. It is an investigational drug that we believe may help people with certain mitochondrial diseases, like the one you have, both in terms of reducing the acidity of your blood and preventing or decreasing nerve and muscle damage. Our belief is based on previous studies that have been conducted in children with mitochondrial diseases of various types. Therefore, a 12 month study has been designed to determine the safety and benefit of taking CoQ10 every day. This will be done by comparing the subjects response to taking CoQ10 for 6 months to taking a placebo for 6 months. A placebo looks, smells, and tastes like the drug being tested (in this case, CoQ10) but has no effect. Placebo studies such as this one are very common in evaluating investigational drugs for any disease and are usually required by the FDA before a drug can be approved.

CoQ10 or placebo will be given as a liquid once per day in the evening, by mouth or feeding tube. The CoQ10 dose will be 10 mg/kg with a maximum dose of 400 mg a day. Neither the subject nor the health care givers will know exactly when subjects are receiving CoQ10 or when subjects are receiving the placebo. However, subjects will receive CoQ10 for at least 6 months. At each visit the subject will be given a seven month supply of CoQ10, nutritional cocktail, and multivitamins to take home and they will be asked to bring back any unused medications at the next visit. At each visit subjects will be given a medication diary to record the time and date that they take the medications that will be provided. This diary should be returned to the study coordinator at the subject's scheduled visit. During the 12 month period that subjects are on the study, they will be expected to stop taking all medications and other supplements except for those provided by the study and those that the study doctor determines are medically needed. Except in the case of an emergency, the subject must contact the study doctor before taking any new medications or supplements. In the case of an emergency, subjects are required to inform the study doctor of the emergency and treatments as soon as possible.

Subjects will be hospitalized on the General Clinical Research Center (GCRC) ward of Shands Hospital for 2-4 days every three to six months. A parent or legal guardian will be expected to stay with the subject. During that hospitalization, physical and intellectual development will be measured by standard tests. The GCRC dietician will ask questions about current diet at each visit and record answers. A general medical history and physical examination (including gross motor function and/or strength tests) will be performed during each visit as well as a six minute walking test. While enrolled in this study, a special "nutritional cocktail" and a Centrum-like multivitamin supplement will be provided for subjects to take daily. The nutritional cocktail has vitamin C, up to 10 mg/kg/day (max. 400 mg/day), riboflavin, up to 2.5 mg/kg/day (max. 100 mg/day), thiamine, up to 2.5 mg/kg/day (100 mg/day), carnitine, up to 10 mg/kg/day (max. 400 mg/day). The nutritive cocktail is in capsule form and the number of capsules that the subject will take will be based on body weight (for every 4 kg. of body weight subjects will receive 1 capsule daily). Each capsule contains: Vitamin C 40 mg, Riboflavin 10 mg, thiamine 10 mg and carnitine 40 mg. The maximum amount of capsules that will be given daily to anyone in this study is 10 capsules daily. A parent or legal guardian will be asked to complete each of eight questionnaires regarding behavioral and developmental, quality of life (5), and sleep. The behavioral and developmental, four of the quality of life (QOL) questionnaires, and the sleep questionnaire should be completed at the 0, 6 and 12 month visits. One of the QOL questionnaires (46 questions) will need to be completed monthly and mailed back to the study center after completion (self-addressed, stamped envelopes will be provided by the study and given to you by the coordinator). We expect that it will take up to 20 minutes to complete the monthly QOL questionnaire and up to 3 hours at the 0, 6 and 12 month visit to complete the rest of the questionnaires.

About 15-20 ml. of blood (3-4 teaspoons) will be obtained during each hospitalization. A urine sample will also be collected during each hospital visit. In females of child-bearing age, urine will also be collected and tested for the presence of HCG (a hormone that determines pregnancy). Within 24 hours of blood and urine collection test results will be assessed by the study physician.