Senataxin is a large 303 kDa protein linked to neuron survival, as recessive mutations cause Ataxia with Oculomotor Apraxia type 2 (AOA2), and dominant mutations cause amyotrophic lateral sclerosis type 4 (ALS4). The gene discussed is SETX; the disease is spinocerebellar ataxia, autosomal recessive, with axonal neuropathy 2.