Class switch recombination Different genetic defects cause HIgM syndrome, the vast majority are inherited as an X-linked recessive genetic trait and most sufferers are male. IgM is the form of antibody that all B cells produce initially before they undergo class switching. Healthy B cells efficiently switch to other types of antibodies as needed to attack invading bacteria, viruses, and other pathogens. In people with hyper IgM syndromes, the B cells keep making IgM antibodies because can not switch to a different antibody. This results in an overproduction of IgM antibodies and an underproduction of IgA, IgG, and IgE.
Hyper-IgM syndrome type 2
Hyper-IgM syndrome type 5
Hyper-IgM syndrome type 1
Hyper-IgM syndrome type 3
Hyper-IgM syndrome type 4
Hyper IgM syndrome
Anti-IgLON5 disease
Wiskott–Aldrich syndrome