Spinocerebellar ataxia type 1

Spinocerebellar ataxia type 1, or SCA1, is a rare autosomal dominant disorder with neurological symptoms including slurred speech, abnormal eye movements and ataxia of gait and stance. The cerebellar dysfunction is progressive and permanent. Symptoms normally begin between the ages of 30 and 40, though juvenile onset occurs, and death typically follows within 10 to 30 years of onset. It is caused by an expanded run of CAG repeats in the ATXN1 gene, which makes an abnormally long glutamine tract in the ataxin 1 protein and damages neurons such as Purkinje cells. No cure is known, so care focuses on managing symptoms. The source gives a worldwide estimate of 1 to 2 people per 100,000, and calls SCA1 the first spinocerebellar ataxia gene to be localized and identified.