Les paraparésies spastiques héréditaires

Hereditary spastic paraplegias (HSPs) are genetically heterogeneous mendelian disorders characterized by weakness and spasticity in the lower limbs associated with additional neurologic signs in “complex” or “complicated” forms. A remarkable number of loci/genes are involved with different inheritances: autosomal dominant, autosomal recessive and X linked. Only a few genes are routinely analyzed: in autosomal dominant forms, SPG4 is the gene most frequently involved which accounts for approximately 40% of all AD-HSP families with generally adult onset, SPG3A represents 10% of all AD-HSP families with generally infancy onset. In autosomal recessive forms, mutations in the recently identified SPG11 gene seem to account for a majority of the complex forms of the disease with atrophy of the corpus callosum. The aim of this review is to describe the clinical and diagnostic features of the various forms of HSP. Genetic testing is progressively more complex and clinical and other information concerning the phenotype is now crucial for choosing an appropriate genetic testing procedure for each patient and permit genetic counselling.