FunctionRNA-editing deaminase involved in somatic hypermutation, gene conversion, and class-switch recombination. Required for several crucial steps of B-cell terminal differentiation necessary for efficient antibody responses.
Tissue specificityStrongly expressed in lymph nodes and tonsils.
Involvement in diseaseDefects in AICDA are the cause of hyper-IgM immunodeficiency syndrome type 2 (HIGM2) [MIM:605258]; also known as hyper-IgM syndrome 2. HIGM2 is an autosomal recessive disorder characterized by normal or elevated serum IgM levels with absence of IgG, IgA, and IgE, resulting in a profound susceptibility to bacterial infections. HIGM2 causes the absence of Ig class switch recombination (CSR), the lack of Ig somatic hypermutations, and lymph node hyperplasia caused by the presence of giant germinal centers.
Sequence similaritiesBelongs to the cytidine and deoxycytidylate deaminase family.