Spinocerebellar Ataxia 1 (SCA1)
SCA 1 shows anticipation, mainly through paternal inheritance.
Molecular genetics and pathogenesis
SCA 1 is due to an expanded CAG repeat in a coding region of the SCA1 gene, encoding ataxin-1, a protein of unknown function. Like the other dominant polyglutamine diseases, the toxic effect is believed to be primarily due to a gain of function of the mutated protein, rather than a lost function of the wild-type.
Ataxia of limbs, gait, speech, eye movements; exaggerated reflexes, extrapyramidal signs, especially parkinsonism and dystonia; spasticity; mild cognitive impairment; peripheral neuropathy. Symptoms usually begin around age 30.
Very few clinical trials have been conducted in spinocerebellar ataxia. A recent double-blind pilot trial in a small number of patients with various forms of ataxia, including SCA-1, indicated that riluzole may offer some benefit for ataxia symptoms (see E-MOVE Article: Riluzole for Cerebellar Ataxia).
Assadi M, Campellone JV, Janson CG, Veloski JJ, Schwartzman RJ, Leone P. Treatment of spinocerebellar ataxia with buspirone. J Neurol Sci. 2007 Sep 15;260(1-2):143-6.