In a study of patients with immunoglobulin A deficiency and common variable immunodeficiency syndrome, two novel APE1 SNPs were identified: Q51H (rs1048945) and one in the 5′ UTR (rs2307490), only the latter showed an association with common variable immunodeficiency syndrome (163). Here, APEX1 is linked to immunodeficiency-centromeric instability-facial anomalies syndrome 1.