we have also seen increased ALT/AST for our child when ferritin is below 500. But interestingly Hemo in Children's hospital in Boston believes in reducing the exjade dosage to a lower level than completely stopping the exjade dose when ferritin hovers around 500. as per him, even with low ferritin, the free redicals are still harmful so chelation should never be completely stopped, it should be reduced. That's what we do for our child - when ferritin hovers at 500, we just do 1 tab of 125 mg Exjade/day...when feritin climbs to 700, we up the dose to 3 tabs of 125 mg exjade/day...This way, we have been able to maintain ferritin between 400 and 700 and kidney functions in normal range....