PPP2R2B and fragile X-associated tremor/ataxia syndrome: RNA-mediated pathogenesis is believed to play a critical role in several other repeat expansion disorders, including Myotonic Dystrophy Type 1 (DM1) and Type 2 (DM2), SCA8, SCA12, Huntington's disease like 2 (HDL2), and fragile X tremor ataxias syndrome (FXTAS) [7], [8].