CHRNA4 and myasthenia gravis: However, the total amount of nAChR antibodies in the serum of MG patients does not seem to correlate with disease severity, suggesting that various nAChR antibodies that bind different regions on nAChR may contribute differently to this disease (Somnier, 1993; Berrih-Aknin, 1995; Mossman et al., 1988; Tzartos et al., 1998).