FMR1 and fragile X syndrome: The highest correlation between FMR1 mRNA levels and OWLS-II LC and OE scores was seen for the FXS blood samples (0.668 and 0.666, respectively), followed by samples collected by buccal swab (0.444 and 0.595, respectively) and hair follicle plucking (−0.189 and −0.286, respectively) (see Tables 6 and 7).