The association signals observed at HTR7 are compelling, as they indicate important genetic effects on both neuroelectrical activity and the risk of alcohol dependence. Although the HTR7 marker shows a stronger association with theta band EROs in the family sample, this does not suggest that the association is only relevant to affected families but that the neuroelectrical effect at this locus is more easily detected on a genetic background with a higher load of AD risk alleles. The HTR7 gene encodes a G-protein-coupled neurotransmitter receptor of the serotonergic system. Serotonin (5-HT) is one of the most widely used neurotransmitters in the brain, whose effects are produced through its interaction with 14 membrane-bound receptors, including the most recently identified receptor 5-HT7, and has been implicated in the etiology of numerous psychiatric disease states, including depression, social phobia, schizophrenia, obsessive-compulsive, migraine, and eating disorders [Naughton et al., 2000; Hoyer et al., 2002; Nichols and Nichols, 2008]. The distribution of 5-HT7 binding sites in discrete areas of the brain, such as the limbic system and thalamocortical regions, overlaps the areas of neuroelectrical activity
