in relation to alcoholism, Nurnberger et al (2002) found evidence for antisocial alcoholism at quantitative trait locus (QTL) 11p. The subtelomeric region of 11p (11p15.5) contains three genes: IGF2 (a growth factor), INS (insulin), and TH (tyrosine hydroxylase) that lie in an interval of less than 50 kb. In addition, this region contains genes (eg, KCNQ1OT1) that code for the M-current and similar potassium channel mediated effects. Finally, two genes important for catecholaminergic expression in the CNS are localized to the 11p15.5 region: TH and the gene that encodes the dopamine receptor D4 (DRD4). Interestingly, many of the genes in area 11p15 are imprinted. These observations are potentially important for alcoholism research because of the role of genetic influences in the etiology of neurological and neurobehavioral abnormalities. Perhaps the same genes involved in brain anomalies are also involved in alcoholism. However, as noted by Dick and Foroud (2003), sequencing of the human genome will make the cataloging of human genes and genetic variation available to researchers who will advance the association of candidate genes with alcoholism. Once replicable associations are established, it will still remain a challenge to identify the causative genetic variants responsible for the role of that gene
