Evidence of a genetic background predisposing to complex regional pain syndrome type 1.

BACKGROUND

Complex regional pain syndrome type 1 (CRPS-1) is a rare, disabling and sometimes chronic disorder usually arising after a trauma. This exploratory study examined whether patients with chronic CRPS-1 have a different genetic profile compared with those who do not have the condition.

METHODS

Exome sequencing was performed to seek altered non-synonymous SNP allele frequencies in a discovery cohort of well-characterised patients with chronic CRPS-1 (n34) compared with population databases. Identified SNP alleles were confirmed by Sanger sequencing and sought in a replication cohort (n50). Gene expression of peripheral blood macrophages was assessed.

RESULTS

In the discovery cohort, the rare allele frequencies of four non-synonymous SNPs were statistically increased. The replication cohort confirmed this finding. In a chronic pain cohort, these alleles were not overexpressed. In total, 25 out of 84 (29.8%) patients with CRPS-1 expressed a rare allele. The SNPs were rs41289586 in , rs28360457 in , rs1126930 in and rs80308281 in . Males were more likely than females to have a rare SNP allele, 8 out of 14 (57.1%) vs 17 out of 70 (24.3%) (Fisher's p=0.023). , , and were all expressed in macrophages from healthy human controls.

CONCLUSION

A single SNP in each of the genes and was associated with developing chronic CRPS-1, with more males than females expressing these rare alleles. Our work suggests the possibility that a permissive genetic background is an important factor in the development of CRPS-1.