Finally, 28 top shared SNPs near PTGER4 (5p13.1) are associated with CD, multiple sclerosis, and self-reported allergy, with other SNPs in the region being associated with immune-related traits (UC, psoriasis, selective IgA deficiency, ankylosing spondylitis, and blood protein levels). The gene discussed is PTGER4; the disease is selective IgA deficiency disease.