Clinical and Pathological Features of Hereditary Ataxiasemsp; Work in the laboratory of TA has been supported by NIH/NINDS grant #1 RO1 NS41547–01. Work in the laboratory of SHS has been supported by Grants from the Luckyday Foundation and the Stangle Ataxia Research Fund

Hereditary ataxias are recognized as a heterogeneous group of diseases based on their clinical and histopathological features. Diagnosis of specific disorders is complicated by the considerable phenotypic variability and marked overlap of clinical features among the hereditary ataxias. Recent progress in the field of molecular and human genetics allowed for identification of genetic loci or mutations responsible for many of these diseases, and DNA testing can now identify the mutation in 60–70% of patients with hereditary ataxia. An increasing number of genetic animal models of hereditary ataxias are becoming available. These genetically engineered animals provide a powerful means to study disease mechanisms that is essential for the development of rational treatment strategies. These animal models are also used to screen available drugs for their efficacy in treating the disease. This chapter aims at reviewing the clinical and histopathological features of inherited ataxias. For the most part, the chapter focuses on the diseases for which the causative genetic mutation is identified.