FNIP1 and Birt-Hogg-Dubé syndrome: Second, it is likely that loss of FLCN is actually responsible for mTOR activation, as is suggested by Baba et al., whose data show that the induction of mTOR is mild in FNIP1−/− mice as compared to FLCN−/− and that FNIP1 deletion fails to phenocopy BHD syndrome [17,43,54].