FMR1 and fragile X-associated tremor/ataxia syndrome: Fragile X-associated tremor/ataxia syndrome is a late-onset condition that is caused by abnormally high numbers of 55–200 CGG-repeats in the 5'UTR of the FMR1 gene (Hagerman and Hagerman, 2016; Salcedo-Arellano et al., 2020).