In addition, agonist autoantibodies active against the sympathetic autonomic nervous system proteins ADRB1, ADRB2 and CHRM2 has been found in approximately one-third of CRPS cases.48–50 CRPS-1 could turn out to be a number of different diseases with the same phenotype, or at least the phenotype could be potentially stratified by SNPs and by sex. Here, CHRM2 is linked to complex regional pain syndrome.