Effect of L-carnitine Supplementation on Phenylalanine and Brain-derived Neurotrophic Factor Levels in Infants and Children With Phenylketonuria

44 patients diagnosed as a case of phenylketonuria will receive l-carnitine at a dose of 100 mg/kg/day for 1 year and then blood sample will examined for level of brain-derived neurotrophic factor levels before and after therapy and another group composed of 44 patients diagnosed as a case of phenylketonuria will not receive l-carnitine and their blood sample will examined for level of brain-derived neurotrophic factor levels treated and untreated patients will compared with healthy children and infants has same age and sex .