Amyotrophic lateral sclerosis: an introduction

Amyotrophic lateral sclerosis (ALS) is a progressive, neurodegenerative disease that results in the degeneration of lower and upper motor neurones in the brain and the spinal cord. Early onset and modern therapies, including assisted ventilation, improve survival in this disease, although its cause remains uncertain. Amongst the possible causes are deficiency of nerve growth factor, deficient glutamate re-uptake, autoimmunity and mutation of superoxide dismutase 1 gene. Additional factors may be industrial pollutants and occupational exposure to chemicals associated with welding and soldering. The criteria for the diagnosis of ALS, proposed by the World Federation of Neurology, are presented together with a review of the clinical features of the disease.