Saccade Velocity as a Surrogate DiseaseMarker in Spinocerebellar Ataxia Type 2

Spinocerebellar ataxia type 2 (SCA2) is an autosomal-dominant disorder mani-festing with gait, limb, and speech incoordination, and with distinctive symptomssuch as early slowing of horizontal eye movements and early neuropathy.1–3 Neuro-pathological analysis has demonstrated severe olivopontocerebellar atrophy (OPCA)early in the course of disease, progressing to involve the anterior horn, substantia ni-gra, thalamus, and somatosensory pathways.4,5 Clinical onset is usually in midlife,but has been observed to range from 1 to 65 years of age, depending on the size ofthe underlying mutation, a CAG (cytosine-adenine-guanine)-trinucleotide repeat ex-pansion in exon 1 of the SCA2 gene...(AU)

Saccade velocity as a surrogate disease marker in spinocerebellar ataxia type 2.

We measured in 82 spinocerebellar ataxia type 2 (SCA2) patients and in 80 controls maximal saccade velocity (MSV) and correlated it to polyglutamine expansion size and disease duration. MSV is strongly decreased in SCA2 patients and is influenced mostly by polyglutamine size.