FMR1 and fragile X syndrome: The fact that even the GM06897 lymphoblastoid cell line, which has 477 repeats, makes some residual FMRP and that FMRP levels increase when the cells are treated with splitomicin, raises the possibility that increased RNA production may lead to increased FMRP production in the ∼40% of individuals with FXS who have repeats of <500 (Sally Nolin, personal communication).