T he cerebellar ataxias are a heterogeneous group of neurodegenerative disorders, characterised by symptoms and signs of cerebellar degeneration, pyramidal and extrapyramidal features, and variable polyneuropathy. Prominent clinical features are signs of cerebellar ataxia, such as uncoordinated gait and uncontrolled co-ordination of hand, speech, and eye movements, while (extra) pyramidal signs...

Onset of the disease is often during the second year of life: there is progressive cerebellar ataxia (initially truncal, with further peripheral extend); ataxia is a constant feature in this disease; oculomotor apraxia, dysarthria, and dystonia; leading to muscular atrophia. Telangiectasia: facial region exposed to sunlight, and eyes (conjunctiva). Combined immunodeficiency (in 70 %): thymus hy...

Ataxia-telangiectasia (A-T) is a rare autosomal recessive neurodegenerative disorder. It is characterized by early-onset, progressive cerebellar ataxia, oculomotor apraxia, choreoathetosis, conjunctival telangiectasias, immunodeficiency, and an increased risk of malignancy. Although A-T is known to be the most common cause of progressive cerebellar ataxia in childhood, there have been no confir...