According to criteria proposed by Jacquemont et al. this was a definite case of FXTASbecause the major criteria consisting of tremor, ataxia and the MRI findings of T2and FLAIR hyperintensities in the middle cerebellar peduncles were fulfilled in apatient with the FMR1 gene premutation.24 Other key features pointing to the diagnostichypothesis were the presence of cognitive decline and mental retardation in agrandson. This evidence concerns the gene FMR1 and Mental deterioration.