Rodriguez-Cortez et al. performed a comparison of CVID patients and healthy individuals, which revealed significant changes in DNA methylation associated with CVID in B cells, specifically the hypermethylation of several genes of relevance in B cell biology, including pik3cd, bcl2l1, rps6kb2, tcf3, and kcnn4 [115]. The gene discussed is TCF3; the disease is common variable immunodeficiency.