Several other genes are also involved in signaling and DNA repair defect in breast cancer such as fanconi anemia (FA) genes (FANCD2, FANCA, FANCC), mismatch repair endonuclease PMS2, mismatch repair genes (MutL homolog 1 (MLH1)), ataxia-telangiectasia, mutated (ATM) and Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) genes [40,41]. The gene discussed is ATM; the disease is Friedreich ataxia.