The muscarinic cholinergic receptor 2 gene (CHRM2) was also associated with alcohol dependence in a linkage study followed up by genotyping candidate genes in the region. Other groups have replicated this finding60, and, like GABRA2, it appears to be strongest in the alcoholics with early onset or comorbid drug dependence61. Again, like GABRA2, an electrophysiological endophenotype focused studies on this gene62, 63.
