QSOX1 and colitis: In a mouse model of a human mutation, deficiency in St6galnac1, a highly conserved ST that generates sialyl‐Tn antigen, resulted in phenotypes closely resembling those of QSOX1 KO animals: a compromised mucus barrier, massive decrease in colon protein sialylation, changes in microbiome composition, and susceptibility to colitis (Yao et al, 2022).