FMR1 and fragile X syndrome: Change (mutation or premutation) in the FMR1 gene sequence on the chromosome X that results in fragile X syndrome (FXS) or fragile X-premutation tremor/ataxia syndrome (FXTAS) are among the leading genetic causes of ASD (Šarac et al., 2011; Ghaziuddin and Al-Owain, 2013).