Ataxia and hereditary disorders

The last decade has seen great changes in the diagnosis of inherited ataxia s. Previously mysterious diseases are now recognized to be caused by specif ic mutations for which genetic screening is readily available. In many case s, the discovery of the molecular basis has broadened the definition of pos sible clinical manifestations of particular inherited ataxias. The type of mutation underlying the more common forms of inherited ataxia-unstable trin ucleotide repeat expansions-helps to explain some of the unusual features o f these diseases. This article reviews recent genetic advances in ataxia. T he aim is not to present an exhaustive summary but rather to provide guidan ce in evaluating ataxia, particularly with respect to recent molecular gene tic findings.