CHRM3 and systemic sclerosis: A study by Kawaguchi et al. found significantly higher titres of antagonistic autoantibodies targeting the muscarinic-3 acetylcholine receptor (M3R) in the sera of SSc patients with severe GI involvement (i.e., malabsorption, pseudo-obstruction and/or need for parenteral hyperalimentation) within 2 years of SSc diagnosis vs. SSc patients without early GI involvement [47].