Together, our data give rise to the possibility that some of the previously reported positive associations can be explained, at least in part, by the high LD between the reported markers and the SNP rs563649 identified in this study (57,58). Furthermore, it is likely that several functional SNPs co-exist within the haplotype, where alternative alleles play specific roles in distinct but related pain phenotypes, are carefully balanced and thus transmitted jointly. This haplotype was observed in 6% of the subjects, thus representing a substantial proportion of the human population and is of clinical significance.
