ANKK1 was also found to associate with the executive attention network in the anterior cingulate gyrus, a dopamine-rich region of the brain (Fossella et al., 2006). A recent study of association between ND and a region spanning ANKK1 and DRD2 reported a putatively functional polymorphism, rs2734849, in an African American sample (Huang et al., 2008); this variant alters the expression level of NF-κB regulated genes (Huang et al., 2008). Further, NF-κB1 gene encoding the transcription factor NF-κB was associated with AD (Edenberg et al, 2008). Another recent extensive analysis of association between AD and a smaller region spanning only ANKK1 and DRD2 from the Collaborative Study on the Genetics of Alcoholism (COGA) showed that the strongest evidence of association is in a linkage disequilibrium (LD) block in the 5′ end of ANKK1 (Dick et al., 2007b). This LD block extends from an upstream intergenic single nucleotide polymorphism (SNP) to exon 2 of ANKK1, which to some degree replicated our finding of an association of AD to ANKK1 (Yang et al., 2007).
