The CACNA2D2 allelic distributions are presented in Figure 5. The minor CACNA2D2 G>A allele was not found in any of the 16 high responders (0%), while 12/44 (27%) of the normal responder group, 6/20 (30%) of the non-responders, and 15/56 (25%) of the control group had this allele (Table 1). Thus, high responders to remifentanil had a higher incidence of the major CACNA2D2 allele than normal responders, non-responders or controls (p < 0.05). There was also a trend for men with the major CACNA2D2 allele to respond better to opioids than men with the minor allele (p = 0.087). In a multivariate model adjusted for age and sex there was a significant association between CACNA2D2 genotype and opioid sensitivity (r = 0.247, adjusted R2= 0.067, p = 0.029).
