The spinocerebellar ataxias (SCAs) are diseases characterized by neurodegeneration of the spinocerebellum. To date, 28 autosomal dominant SCAs have been described and seventeen causative genes identified. These genes play a role in a broad range of cellular processes. Recent studies focused on the wild type and pathogenic functions of these genes implicate both gene expression and glutamate-dependent and calcium-dependent neuronal signaling as important pathways leading to cerebellar dysfunction. Understanding how these genes cause disease will allow a deeper understanding of the cerebellum in particular as well as neurodegenerative disease in general.