<unk>  describes a group of primary immune deficiency disorders characterized by defective CD40 signaling; via B cells affecting class switch recombination (CSR) and somatic hypermutation. Immunoglobulin (Ig) class switch recombination deficiencies are characterized by elevated serum Immunoglobulin M (IgM) levels and a considerable deficiency in Immunoglobulins G (IgG), A (IgA) and E (IgE). As a consequence, people with HIGM have decreased concentrations of serum IgG and IgA and normal or elevated IgM, leading to increased susceptibility to infections.
Hyper IgM syndrome
Hyper-IgM syndrome type 5
Hyper-IgM syndrome type 2
Hyper-IgM syndrome type 3
Hyper-IgM syndrome type 4
Hyper-IgM syndrome type 1
Anti-IgLON5 disease
Common variable immunodeficiency