Common variable immunodeficiency (CVID) is a term used to classify a collection of related genetic disorders affecting roughly 1 in 10,000 to 1 in 50,000 globally and characterized by the absence or severe deficiency for IgG, IgA, and occasionally IgM antibody isotypes (Salzer et al., 2012). The gene discussed is CD40LG; the disease is common variable immunodeficiency.