immunoglobulin A deficiency 2 (MONDO_0012291) is any selective IgA deficiency disease in which the cause of the disease is a mutation in the TNFRSF13B gene. Also known as: Immunoglobulin a deficiency type 2, TNFRSF13B selective IgA deficiency disease, immunoglobulin a deficiency 2, selective IgA deficiency disease caused by mutation in TNFRSF13B.