The heterogeneity in this polymorphism was contributed mainly by Zhang et al. Removal of this study from meta-analysis gave 0% (p > 0.05) (Allelic contrast: Asian: p = 0.40; APOE ε4+: not available (NA); recessive model: Asian: NA; APOE ε4+: NA) heterogeneity and the result remained none significant, which showed that it had the highest effect on the correction of 5HT2A and AD. Here, APOE is linked to Alzheimer disease.