FMR1 and fragile X-associated tremor/ataxia syndrome: However, lymphoblasts have been used successfully to study the roles of FMR1 mRNA, antisense RNA and FMR1 protein expression in PM carriers, FXTAS and Fragile-X patients (Ladd et al., 2007; Hagerman and Hagerman, 2013), and the present study provides unequivocal evidence for the relationship of the FMR1 mRNA levels assessed in the lymphoblasts and the severity of the white matter lesions.