Autosomal recessive ataxias

Abstract

Since the description of Friedreich ataxia more than 140 years ago, the phenotypic description of the autosomal recessive cerebellar ataxias has been a perpetually evolving fi eld. These disorders classically present with a varying combination of gait disturbance, truncal and appendicular ataxia, dysarthria, eye movement abnormalities, sensorimotor neuropathy, pyramidal and extra-pyramidal tracts involvement, and other systemic manifestations. The progress of genetics has recently allowed a more accurate diagnostic work-up, which brought to light the great phenotypical heterogeneity of the genetically defi ned disease entities. We review here the clinical, genetic and molecular features of the most frequent and best-defi ned autosomal recessive ataxias: Friedreich ataxia, autosomal recessive spastic ataxia of Charlevoix-Saguenay, ataxia-telangiectasia, ataxia-telangiectasialike disorder, autosomal recessive cerebellar ataxia types 1 and 2, ataxia with oculomotor apraxia types 1 and 2, ataxia with vitamin E defi ciency, and abetalipoproteinemia. Emphasis will be placed on the key clinical features that enable discrimination between these complex diseases.