Our analysis also revealed downregulation of the serum heme scavenger HPX in UC patients, yet upregulation was seen in CD patients with the PTPN2 risk allele (Figure 1A,B), suggesting differential regulation of this protein between the IBD subtypes; however, studies have not fully investigated the expression of iron handling proteins in CD patients compared to UC patients. Here, PTPN2 is linked to inflammatory bowel disease.