Rs7597593 has also been implicated for influencing ZNF804A mRNA expression, but the association was found only in females (Zhang et al., 2011). We did not find any evidence for sex-by-genotype interactions in our study. Overall, we replicated the previously observed rs7597593 association with heroin addiction in European Americans, but not in African Americans. Rs7597593 may tag a different causal variant with varying linkage disequilibrium across the ancestral groups, which may be identified by fine mapping this region using a large sample of African Americans.
