They include ataxia with oculomotor apraxia type 1 (AOA1) due to mutation in APTX2, ataxia with oculomotor apraxia type 2 (AOA2) caused by mutations in SETX3, ataxia telangiectasia (AT) due to mutation in ATM4, and the rarer AT like disorder (ATLD) linked to mutations in MRE11. The gene discussed is MRE11; the disease is ataxia telangiectasia.