The most common of these is AOA2 (also known as spinocerebellar ataxia with axonal neuropathy type 2 [SCAN2]) caused by mutation in senataxin (SETX), an RNA/DNA helicase involved in maintenance of genome integrity in response to DNA replication stress from DNA:RNA hybrid R‐loop formation during transcription, chromosomal stability, DNA damage, autophagy, transcriptional regulation, RNA processing and degradation, and the innate immune response (see Fig 1).56, 57, 58. The gene discussed is SETX; the disease is Spinocerebellar ataxia with axonal neuropathy type 2.