Collectively, these findings are in direct contrast to a previous Fragile X syndrome study, where increased cortical thickness was associated with poorer performance on multiple domains of the Stanford-Binet Intelligence Scale.60 In that study, the Fragile X syndrome findings were hypothesised to reflect inefficient synaptic pruning due to FMRP deficiencies.60 As such, other mechanism(s) and pathways discussed below are likely to underlie these neuroanatomical–executive function relationships in PM females without FXTAS. The gene discussed is FMR1; the disease is fragile X-associated tremor/ataxia syndrome.