Addition of age and sex as covariates to this model reduced the previously observed significance in the aMCI group (R2 = 0.36, semi-partial correlation coefficient = − 0.48, P = 0.09), while the association between global Aβ deposition and hippocampal SV2A in the dementia group remained non-significant (R2 = 0.24, semi-partial correlation coefficient = 0.07, P = 0.72). The gene discussed is SV2A; the disease is dementia.