Activation-induced cytidine deaminase (AID)

Activation-induced cytidine deaminase (AID) is a DNA/RNA-editing enzyme encoded by the *AICDA* gene and is the evolutionary founding member of the APOBEC protein family. It is responsible for cytidine-to-uracil deamination in single-stranded DNA, which is critical for somatic hypermutation and class switch recombination in B cells—processes that diversify antibody specificity and enable adaptive immunity. AID also influences epigenetic gene regulation by DNA demethylation and has a tightly regulated expression and activity to prevent mutagenesis and carcinogenesis. Mutations or dysregulation of AID cause clinical conditions such as Hyper-IgM Syndrome type 2 immunodeficiency and contribute to the development of lymphomas and possibly other malignancies. No approved drugs currently target AID directly; therapeutic interest focuses on its pathogenic overactivity in cancer and immunodeficiency.

Other names

AICDAHIGM2CDA2ARP2cytidine aminohydrolasesingle-stranded DNA cytosine deaminaseHEL-S-284epididymis secretory protein Li 284AID proteinAPOBEC memberintegrated into Burkitt's lymphoma cell line Ramos

Not applicable; currently, drugs targeting AID are not in established clinical use. Theoretical approaches could involve inhibition or modulation of its deaminase activity or regulation of its expression