AID deficiency

Hyper-IgM syndrome type 2 (HIGM2) is characterized by normal or elevated serum IgM levels with absence of IgG, IgA, and IgE, resulting in a profound susceptibility to bacterial infections. There is an absence of immunoglobulin class switch recombination (CSR), a lack of immunoglobulin somatic hypermutations, and lymph node hyperplasia caused by the presence of giant germinal centers. This is an autosomal recessive disorder responsible for approximately 30% of Ig deficiencies with increased IgM.

Alternative names


Activation-induced cytidine deaminase deficiency

Activation-induced cytidine deaminase

Non-X-linked hyper-IgM syndrome

Hyper-IgM syndrome 2

Autosomal recessive hyper-IgM immunodeficiency

Autosomal recessive hyper-IgM syndrome


  • Deficiencies predominantly affecting antibody production
    • Defects of class-switch recombination and somatic hypermutation (Hyper-IgM syndromes) affecting B cells


Autosomal recessive


#605258 Immunodeficiency with hyper-IgM, type 2

*605257 Activation-induced cytidine deaminase; AICDA


1: 2,000,000 births/year