ATM and Ataxia-telangiectasia: As one of the DNA repair genes, ataxia-telangiectasia mutated (ATM) gene which is responsible for the multisystem autoxomal recessive disorder ataxia-telangiectasia (A–T), plays a crucial role in the recognition, signaling and repair of DNA damage, especially DNA double-strand breaks (DSBs) [4], [5].