CHRNA4 and Alzheimer disease: In AD subjects, a positive correlation was also shown between nAChRα4 and nAChRα3 (rho = 0.762, p = 0.028) and between nAChRα4 and nAChRβ4 (rho = 0.717, p = 0.029), whereas a negative moderate correlation was observed between nAChRα7 and nAChRα3 (rho = − 0.683, p = 0.042) and between nAChRα7 and nAChRα4 (rho = − 0.683, p = 0.042).