Several disease states marked by cognitive deficits, most prominently schizophrenia and Alzheimer’s disease, involve nicotinic acetylcholine receptor (nAChR) hypofunction (Adams and Stevens 2007; Hong et al. 2011; Kendziorra et al. 2011; Perry et al. 2000; Petrovsky et al. 2010; Wing et al. 2012) and may benefit from treatments that enhance nAChR activity (Levin and Rezvani 2002; Singh et al. 2004). Here, CHRNA4 is linked to early-onset autosomal dominant Alzheimer disease.