The underlying causes of<unk>  are largely obscure. Genetic mutations can be identified as the cause of disease in about 10% of people, while familial inheritance accounts for 10–25% of cases. Rather than arising from a single genetic mutation,<unk>  seems to result from variety of mutations that all contribute to a failure in antibody production. Mutations in the genes encoding ICOS, TACI, CD19, CD20, CD21, CD80 and BAFFR have been identified as causative of<unk> . Susceptibility to<unk>  may also be linked to the major histocompatibility complex (MHC) of the genome, particularly to DR-DQ haplotypes. A mutation in the NFKB2 gene has recently been shown to cause<unk> -like symptoms in a murine model. The frequency of this NFKB2 mutation in the<unk>  population is, however, yet to be established.
Common variable immunodeficiency
Severe combined immunodeficiency
X-linked severe combined immunodeficiency
X-linked agammaglobulinemia
Chronic granulomatous disease
Primary immunodeficiency
Wiskott–Aldrich syndrome
Combined immunodeficiencies