APOE genotype is associated with left-handedness and visuospatial skills in children

We sought to investigate whether apolipoprotein E (APOE) genotype is associated with unique profiles of cognitive functioning during early-life. School-aged children (N = 147) received standardized achievement tests, the Rey-Osterrieth Complex Figure Test (Copy Condition; RCFT-CC), assessment of hand dominance for writing, and buccal swab testing to determine their APOE genotype. Significant differences were found on the RCFT-CC, with ɛ2-positive children performing worse on this measure relative to both ɛ3/3 (p = 0.032) and ɛ4-positive children (p = 0.018). Further, a higher prevalence of left-hand dominance for writing was observed among ɛ2-positive children (29.2%) relative to ɛ3/3 (8.9%) and ɛ4-positive children (6.1%; p = 0.012), although this finding did not account for the observed group differences on the RCFT-CC. Findings raise the possibility that in childhood, the ɛ2 allele may be associated with: (a) decreased functioning in certain cognitive domains; (b) factors associated with atypical hemispheric dominance. Results may be consistent with the theory of antagonistic pleiotropy, which suggests that APOE may have different protective effects at different developmental stages.