However, in sIgAD several linkage studies were able to demonstrate an association to HLA-DQ/DR loci [22] as well as IFIH1, a locus associated with type 1 diabetes and systemic lupus erythematodes [23], strongly suggesting an autoimmune origin in CVID/sIgAD. The gene discussed is IFIH1; the disease is selective IgA deficiency disease.