An association between HLA-DR13 and patients with complex regional pain syndrome (CRPS) who progressed towards multifocal or generalized tonic dystonia was recently reported. We now report on a new locus, centromeric in HLA-class I, which was significantly associated with a spontaneous development of CRPS, suggesting an interaction between trauma severity and genetic factors conferring CRPS susceptibility. Additionally, an association with the D6S1014 locus was found, supporting the previous finding of an association with HLA-DR13.