is likely that susceptibility to disease is comprised of multiple, relatively common genetic variants each of which confers only small to modest risk in conjunction with environmental factors, a model of disease that will require approaches that increase the number of target genes and single nucleotide polymorphisms (SNPs) investigated. Nonetheless, in the literature on AN, some associations have been replicated, with the accumulated data suggesting the involvement of HTR1D and OPRD1 [Bergen et al., 2003; Brown et al., 2006], SLC6A4 [Gorwood, 2004], and BDNF [Ribases et al., 2004; Gratacos et al., 2008].
