back to the list

Ataxia with Oculomotor Apraxia - APTX

AOA1

APTX

Clinical Features

Ataxia with Oculomotor Apraxia (AOA1) is a slow, progressive cerebellar ataxia beginning in childhood (approx. 2-16 years of age). The initial symptoms are most often gait instability followed by cerebellar symptoms, first with dysarthria, then with dysmetria of the upper extremities and intention tremor. Eye movement dysfunction in the form of oculomotor apraxia also develops a few years after the onset of ataxia and leads to an external ophthalmoplegia. Areflexia  often develops early on, followed by increasing signs of peripheral axonal motor neuropathy. Choreiform or dystonic movement disorders of the upper extremities are also common.  In most patients, mental function remains intact.

Mutations in the Aprataxin (APTX) gene can be associated with muscular Coenzyme Q10 deficiency; patients may show signs of clinical improvement with Coenzyme Q10 therapy.

Genetic Information

AOA1 is an autosomal recessive disease caused by mutation in the Aprataxin (APTX) gene located on chromosome 9 (9p13.3).

Prevalence

The exact prevalence is not known. Studies show that APTX mutations can be detected with varying frequency in up to 20% of patients with autosomal recessive ataxia.

Diagnostic