Figure 1
From: Mouse models of the fragile X premutation and fragile X-associated tremor/ataxia syndrome
Most individuals in the general population have between 5 and 54 CGG trinucleotide repeats in the 5′-UTR of FMR1 . Repeat length in the fragile X premutation range is 55 to 200, resulting in an elevation in FMR1 mRNA levels, a moderate decrease in FMRP and an increased risk of developing FXTAS. Repeat size in the full mutation is >200; FMR1 transcription is silenced due to DNA hypermethylation, and the absence of FMRP results in fragile X syndrome. (Adapted from [9].) FMRP, fragile X mental retardation protein; FXTAS, fragile X-associated tremor/ataxia syndrome.