Recently, linkage analysis of a community-based sample of Australian adults detected a suggestive linkage peak on human chromosome 5p with a LOD score of 2.2 (58). A genome-wide scan performed with community samples recruited through the University of California, San Francisco (UCSF) Family Alcoholism Study identified several suggestive regions linked with DSM-IV alcohol dependence (on human chromosomes 1, 2, 8, 9, 18, and 22) (50). Unfortunately, there is little consensus among studies regarding the location of linkage signals for alcohol dependence. This may be due to underlying genetic heterogeneity in the risk for alcohol dependence, with many genetic loci contributing to risk. This is probably compounded by the fact that all of these studies were underpowered to detect genes of small effect size (110).
