The additional breakdown of immunological tolerance to nuclear antigens such as gp210 at an early stage (stage 1–2) is the second critical step for this type of progression.[21] Based on the above, the current case verified the hypothesis that AMA-positive PBC could be transformed to AMA-negative PBC for a limited period during disease progression because the AMA status changed from an initial positive to negative or weakly positive after the initiation of UDCA therapy. This evidence concerns the gene NUP210 and primary biliary cholangitis.