Safety Study for the Use of Rapamycin in Children With Familial Adenomatous Polyposis

This is a 2-dose rapamycin safety study, with a target through level of 3 to \<5 ng/ml for the first 3 months and 5-8 ng/ml for the next 3 months for each of the included patients. To avoid the possible cumulative effect, the two treatment phases will be separated by a 3-weeks wash-out period.