These indicated that the co-methylation of SIX6 and SOX1, as well as the co-methylation of SIX6, RARB and SOX1, was negatively associated with ADC; the latter association being more significant (SIX6 and SOX1: OR, 0.243; 95% CI, 0.06–0.98; P=0.045; SIX6, RARB and SOX1: OR, 0.008; 95% CI, 0.001–0.149; P=0.007). Here, SOX1 is linked to AIDS dementia complex.