A Study of the Role of Methylenetetrahydrofolate Reductase (MTHFR) Gene Polymorphism in Children With Attention Deficit Hyperactivity Disorder Khaled Ismail Abd El-Shakoor1, Tarek Mostafa Kamal2, Eman Ahmed Zaky3, Howida Hossny ElGebaly4. 1: Pediatric Specialist, Ministry of Health, Medical student at Medical Studies Department, Faculty of Postgraduate Childhood Studies, Ain Shams University, Egypt. 2: Consultant of Human Genetics, Faculty of Medicine - Ain Shams University, Egypt. 3: Profes