AICDA: Proteins and Enzymes

AICDA, also known as AID, is a 24 kDa cytidine deaminase that converts deoxycytidine to deoxyuridine in single stranded DNA. Its expression is restricted to activated lymph node and tonsillar B cells and is required for terminal B cell differentiation. Loss of function mutations of AICDA cause severe humoral immunodeficiency by preventing immunoglobulin class switching and somatic hypermutation. Human AICDA shares 92% - 95% amino acid sequence identity with bovine, canine, and mouse AICDA.