A 6-month-old child presented with multiple episodes of seizures for past 2.5 months. The child was admitted to the ward. He had frequent episodes of hypoglycemia which precipitated the seizures. O/E, Hepatosplenomegaly Sho stature Thin extremities Doll like facies Lab findings revealed hyperuricemia, lactic acidosis, hyperlipidemias Which enzyme deficiency is responsible for this disorder?