The comparison of the change in both FSIQ and PIQ between the first and subsequent visit between FXTAS subjects with and without an APOε2 allele (n = 14, n = 51, respectively), by APOε4, did not differ significantly by the presence of an APOε2 allele, regardless of APOε4 status. Here, APOE is linked to fragile X-associated tremor/ataxia syndrome.