Patient's blood glucose levels were normal by GOD - POD method. But urine shows positive Benedict's test. The reason for disparity in results is :

Benedict's test positive means reducing sugar is present in urine. Both fructose and galactose are reducing. But if blood glucose is normal, then it cannot be fructosemia because fructose accumulation causes hypoglycemia as fructose-1-P inhibits glycogenolysis by inhibiting Glycogen phosphorylase. So the answer is galactosemia, because in glactosemia, blood glucose is normal. In both fructosemia and galactosemia liver is affected but hypoglycaemia occurs only in fructosemia. (See fig below) NOTE: Benedict's test is not answered by sucrose since it's a non-reducing sugar.