MMP9 and fragile X syndrome: Interestingly, in a recent study by Abdallah et al., [16], amniotic fluid samples for 331 ASD cases and 698 frequency-matched controls were analyzed for levels of MMP-9 along with other biomarkers utilizing a Danish historic birth cohort and Danish nationwide health registers Our results showed elevated levels of MMP-9 in ASD cases compared with controls and this was unrelated to FXS.