Including a covariate for cholinesterase inhibitor use did not change the results: F(2,92) = 4.4, p = 0.02; p(HC,MCI-AD) = 0.66, p(HC,MCI-LB) = 0.01, p(MCI-AD,MCI-LB) = 0.26. The gene discussed is BCHE; the disease is Alzheimer disease.