2021-04-302021-04-302021https://hdl.handle.net/20.500.12503/30608Purpose: The effects of many genes involved in the pathogenesis of chronic low back pain (CLBP) are not fully understood, especially concerning racial variation. This study aims to determine if variations of the serotonin receptor gene HTR2A, which has been implicated in psychological and pain disorders, correlate to differences in clinical outcome measures of patients with CLBP in the PRECISION Pain Research Registry. Methods: The base population includes 283 (68.4%) Caucasians and 131 (31.6%) African Americans who were genotyped for their haplotype in 2 haploblocks: A (rs6313;A/G, rs6311;T/C, rs1928040;A/G, rs9567746;A/G) and B (rs7997012;A/G, rs7330636;T/C). Race-specific Kruskal-Wallis analyses were used to determine differences in outcome measures when comparing haplotypes within haploblocks. Separate regression analyses looked at whether haplotypes that are overrepresented in one racial group versus the other had effects on the same outcomes. Results: There were differences in scores for the Roland-Morris Disability Questionnaire (RMDQ) (p=0.04), pain catastrophizing (PCS) (p=0.04), and pain self-efficacy (PSEQ) (p< 0.01) within haploblock A for African Americans. There were also differences in the RMDQ (p=0.02) and PSEQ (p< 0.01) scores within haploblock B for Caucasians. Regressions showed having at least one allele with the haplotype GC in haploblock B is associated with a lower numerical rating scale value for pain intensity after adjusting for additional variables (beta=-0.59; p=0.02). Conclusions: Haplotypes of HTR2A may have a relationship with the pain intensity, disability, and pain response of CLBP patients. Further studies would look at additional race-specific factors and their interplay with HTR2A.enposter