SETX and amyotrophic lateral sclerosis type 4: Human senataxin, the mammalian Sen1 homolog, was initially identified when mutations causing ataxia oculomotor apraxia 2 (AOA2) and amyotrophic lateral sclerosis type 4 (ALS4) were mapped to the senataxin gene (SETX) (reviewed in James and Talbot, 2006; Palau and Espinós, 2006).