has subject area Carrier Proteins - Receptors, Nicotinic Chemically-Induced Disorders - Tobacco Use Disorder Disease Attributes - Genetic Predisposition to Disease Exons Female Genetic Variation Genotype - Genetic Predisposition to Disease Humans Male Membrane Proteins - Receptors, Nicotinic Membrane Proteins - Receptors, Nicotinic Mental Disorders - Tobacco Use Disorder Receptors, Cell Surface - Receptors, Nicotinic Receptors, Cholinergic - Receptors, Nicotinic