Recently, evidence has been obtained that active sialylation could be due to estrogen, which induces the expression of beta-galactoside alpha-2, 6-sialyltransferase 1 (St6gal1), which could explain the difference in the incidence of RA between women and men and among women before and after menopause [98]. The gene discussed is ST6GAL1; the disease is rheumatoid arthritis.