In the subgroup analysis, MTHFR C677T TT genotype was associated with increased AD risk in East Asian (RR = 1.19, 95% CI [1.07, 1.32], p = 0.0015 for TT genotype), while no significant associations in Caucasian, South Asian, Middle Eastern, African, or mixed populations (Table 1). The gene discussed is MTHFR; the disease is Alzheimer disease.