Statistically significant association was found between the pain-sensitivity score and SNP rs563649 in the sliding window of size 1 (SW1), where the CHM becomes an allelic trend test (P = 0.0007). When SW2 was applied, three significant associations were observed (Table 3). The associations of the pain score with the haplotypes rs3798678–rs563649 (P = 0.0028) and rs563649–rs9322446 (P = 0.0018) most likely reflect the effect of SNP rs563649 identified with SW1. Significant associations of the pain score with the haplotype rs2075572–rs533586 (P = 0.0007) identified a new potentially functional genetic variant of OPRM1. In each of the following SW approaches, associations between the pain score and haplotypes were significant for each haplotype containing SNPs rs563649, or haplotype rs2075572–rs533586, or both. The associations for haplotypes starting with either SNP rs563649 or SNP rs2075572 remained significant after the Bonferroni correction for multiple testing within each window size (P = 0.0022 for the highest number of tests for SW1 (Supplementary Material, Fig. S2).
