Nitric Oxide Production in MELAS Syndrome

What does the study involve? Individuals with MELAS syndrome will be admitted twice to the General Clinical Research Center (GCRC) at Texas Children's Hospital. Each time they will stay for five days, during which a special diet will be provided. Nitric oxide production will be measured by stable isotopes infusion technique that involves placing small tubes in veins (IV catheter), blood sampling, and injecting a harmless stable isotope. Stable isotopes are forms of normal compounds that can be measured accurately. They are not radioactive and there are no known risks to giving them; they are already part of your body in small amounts. During the first admission nitric oxide levels will be measured, then arginine supplementation will be provided for 48 hours, after which nitric oxide levels will be re-measured to determine the effect of arginine supplementation. During the second admission, the effect of citrulline supplementation will be measured. Who can participate in the study? Adults or children affected with MELAS syndrome and carrying the DNA change that causes the condition (3243 A\>G mutation) can participate. Adults without MELAS disease will be recruited to participate as control subjects. How to get more information? Subjects interested in participation or getting more information can contact Dr. Ayman El-Hattab at email: elhattab@bcm.edu, office phone: 832-822-4289, cell phone: 646-660-5666, or pager: 832-824-7243 (5523).