In Chinese ulcerative colitis patients (n = 527) versus controls (n = 574), TCN2 rs1801198—but not rs9606756—was linked to HHcy, heightened intestinal inflammation, and lower B12/folate status; similar findings emerged in Canada and Greece, though a Turkish cohort found an inverse Hcy–folate correlation, highlighting ethnic and methodological variability (Akbulut 2010; Zezos 2005; Peyrin‐Biroulet et al. 2007; Zheng et al. 2017; Vagianos and Bernstein 2012; Peyrin‐Biroulet et al. 2007; Oberley and Yang 2013; Zheng et al. 2017). The gene discussed is TCN2; the disease is ulcerative colitis.