The sample of the Comorbidity and Trauma Study, a genetic association study of heroin dependence, consists of Australian heroin dependent cases ascertained from opioid replacement therapy clinics and controls ascertained in nearby economically disadvantaged neighborhoods. The assessment included a screening instrument for BPD, used previously in Australian population surveys. Genotypic and BPD phenotypic data were available for 1439 cases and 507 controls. We examined the association of 1430 candidate gene SNPs with BPD phenotypes.
One or more NRXN3 SNPs were nominally associated with all BPD phenotypes; however, none met the conservative significance threshold we employed to correct for multiple testing. The most strongly associated SNPs included rs10144398 with identity disturbance (p = 4.9 ¡Á 10?5) and rs10151731 with affective instability (p = 8.8 ¡Á 10?5). The strongest association with screening positive for BPD was found for the NRXN3 SNP, rs10083466 (p = .0013). Neither the correlation of BPD phenotypes nor the linkage disequilibrium relationships of the SNPs account for the number of observed associations involving NRXN3 SNPs.
Our findings provide intriguing preliminary evidence for the association of NRXN3 with BPD phenotypes. The strongest associations were found for traits (i.e., affective instability; identity disturbance) also observed with other disorders.