[Neurodegenerative diseases of the spinal cord].

Numerous classifications have been applied to describe degenerative diseases of the spinal cord before the era of molecular analysis. The present challenge is to match in an appropriate manner old and new clinical classifications with the results of genetic analysis. This work is now well advanced for spinocerebellar degeneration but needs to be developed for hereditary spastic paraplegia, spinal muscular atrophies and amyotrophic lateral sclerosis. The widening of clinical spectrum observed in hereditary neurodegenerative diseases of the spinal cord raises the question of modulating factors (environmental or genetic). Clinicians in charge of patients with progressive spinal cord signs should bear in mind that the field of degenerative diseases is a moving one and that a degenerative aetiology has to be suspected more widely than in the past.