Ataxia with Oculomotor Apraxia Type 2 (AOA2) and a form of adolescent ALS (amyotrophic lateral sclerosis type 4) are caused by mutations in the Senataxin (SETX) gene, which encodes a helicase that resolves R-loops during transcription termination [69]. The gene discussed is SETX; the disease is spinocerebellar ataxia, autosomal recessive, with axonal neuropathy 2.