AOA2 belongs to a group of autosomal recessive cerebellar ataxias (ARCA) which also includes Ataxia with Oculomotor Apraxia Type 1, Ataxia-Telangiectasia and Ataxia-Telangiectasia-Like-Disorder. It is characterized by gait ataxia, choreoathetosis, myoclonus, peripheral neuropathy, cerebellar atrophy, oculomotor apraxia and raised alpha-fetoprotein levels. Creatine Phosphokinase levels may also be elevated. AOA2 is caused by mutations in the SETX gene. Unlike AOA1, AOA2 does not show reduced levels of albumin and the chorea and myoclonus do not abate with time. It also has a later onset, starting in adolescence. It is a highly progressive disorder and most patients become wheelchair bound by the third or fourth decade of life. AOA2 has been found to occur in 1 in 900,000 individuals.
Diagnosis is made based on clinical features, levels of alpha-fetoprotein, presence of cerebellar atrophy and via genetic testing of the SETX gene. Treatment options are currently limited to the management of symptoms with physical therapy, speech therapy, mobility aids and special education.