ADAR (Adenosine Deaminases Acting on RNA) comprises enzymes that edit adenosine to inosine, including ADAR1, ADAR2, and ADAR3, primarily expressed in mammals. These enzymes are crucial for RNA editing, especially in the nervous system. ADARs are generally localized in the nucleus, modifying the nucleotide sequences of messenger RNAs and microRNAs, affecting protein expression and function. Specific expression and mutations in ADAR genes are linked to various neurodevelopmental and functional disorders, such as epilepsy and depression.