Metformin in Children With Fragile X Syndrome

The patients in this group will be obtain Metformin starting from 50mg everyday at night, and gradually increase to maximum tolerable dose of 1-2g per day according to weights of patients for 6 months.

The patients in this group will be obtain starch tablets (which had same appearance and size comparing to Metformin) starting from 50mg everyday to 1-2g per day according to weights of patients for 6 months.