Of special interest is a growing body of evidence that genetic anomalies impact some of the same brain areas that are vulnerable to the effects of alcoholism, and those that are involved in emotional processing. For example, Yamasaki et al (2003) found that the human UBE3A gene (which shows brain-specific partial imprinting, ie, it has an alteration in chromatin affecting its expression but not its DNA sequence) was expressed predominantly in the limbic system (including the hippocampus), in cerebellar Purkinje cells, and in the olfactory bulbs. (Imprinting is a reversible form of gene inactivation but is not a mutation.) With the possible exception of the olfactory bulbs, all of the regions reported by Yamasaki et al (2003) to be affected by UBE3A are known to be affected by chronic alcoholism. As we noted earlier in the section, Genetics of temperament 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
