Anecdotal evidence suggests that synesthesia may be heritable[4], and family linkage studies have supported this possibility [5–7],although none has yet identified a specific genetic mechanism bywhich synesthesia is transmitted. One genetic linkage analysis of five synesthetic families found evidence of linkage to chromosome16q in two of the families [7]. Specifically, results from this studypointed to the 16q12.2-23.1 region which contains 343 genes, manyof which are expressed in the brain. The authors highlighted six ofthese as candidate genes that may fit the profile of synesthesia;however, no variants or polymorphisms of these genes emergedin their analysis of affected individuals. Another study deter-mined significant linkage to chromosome 2q24 (HLOD = 3.025,p = .047), and also identified suggestive linkage to several otherchromosomal loci [5]. These results suggest the possibility thatmultiple genes independently influence the development ofsynesthesia