CHRM3 and primary biliary cholangitis: In this respect, it is of interest that the T allele of the receptor is overrepresented in PBC, as compared to controls, probably due to a cholinergic receptor muscarinic 3 (CHRM3) SNP rs4620530 polymorphism in these patients, and it was hypothesized that it may be a potential risk for the development of PBC (48).