Genetics of ataxias: hereditary forms.

WHAT ARE HEREDITARY ATAXIAS? Ataxia is a neurologic disorder in which there is loss of coordination of movement. It can result from dysfunction of the cerebellum and brain stem and their afferent or efferent pathways. The etiology of ataxia can be divided into 3 main categories: acquired, sporadic, and hereditary. Hereditary ataxias are one of the largest groups of hereditary progressive neurodegenerative diseases with an estimated prevalence for all ataxias of 3– 4 per 20,000. Although there is no present curative therapy for hereditary ataxias, novel treatments aim to impact the disease process at the molecular level. Neuroimaging, particularly MR imaging, should be performed in all patients with suspected hereditary ataxias. Neuroimaging can help to make the correct diagnosis, identify treatable causes, monitor disease progression, and exclude secondary causes. The objective of this vignette is to describe the heterogeneous group of hereditary ataxias and to discuss their diverse clinical presentations, imaging characteristics, and diagnostic challenges.