Furthermore, subgroup analysis stratified by ethnicities and APOE ε4 was performed and showed no obvious difference (Ethnicity: p = 0.1; APOE ε4: p = 0.55), implying that the ethnicity and APOE ε4 exerted no influence on the association between the 5HT2A C102T polymorphism and risk of AD. Here, HTR2A is linked to Alzheimer disease.