The site identified on chromosome 2 near 211 cM (LOD = 2.6) for DSM-IV cannabis dependence in the UCSF Family Alcoholism Study appears to be in the same general region (within 30 cM) as a site identified in the COGA dataset for comorbid alcohol dependence and major depression [Nurnberger et al., 2001], and for subjective response to alcohol [Schuckit et al., 2001] using microsatellite markers and for alcohol dependence using SNP genotyping [Agrawal et al., 2008d]. It also appears to be near a site for alcohol dependence identified in multiplex families in Pittsburgh [Hill et al., 2004], and for heavy cocaine use [Gelernter et al., 2005] and opioid dependence [Gelernter et al., 2006] in African Americans. Additionally, this site was identified by a previous genome scan for nicotine dependence in the UCSF family study [Gizer et al., unpublished work]. Thus, this site appears to harbor genes that confer risk for a number of different substance-related phenotypes.
