Amyotrophic lateral sclerosis: concepts in pathogenesis and etiology.

The ALS symposium in Vancouver was the first of its kind in Canada and was a contribution from both American and Canadian investigators. The main points presented were (1) a definition of what is truly ALS, in the clinical and pathological sense, based on what is called "classical" ALS: (2) how neurons may be cultured to provide a valuable experimental tool; (3) the significance of lipid abnormalities in ALS and the characterization of the ALS-like syndromes produced by hexosaminidase A deficiency; (4) the possible role of autoimmune disease as it may accompany classical ALS and nerve growth factor derived from skeletal muscle; (5) the western Pacific form of ALS as it has been intensely studied and has given rise to two hypotheses on pathogenesis: mineral toxicity caused by secondary hyperparathyroidism and poisoning through ingestion of the cycad seed, and (6) the possible abiotropic interaction of one or many environmental toxins over a lifetime with the aging nervous system, depleting it of its frail reserve of neurons.