Type : Phenotype or locus, molecular basis unknown;
Description : For a phenotypic description and a discussion of genetic heterogeneity of amyotrophic
lateral sclerosis (ALS), see ALS1 (105400). ALS is a degenerative disorder characterized
by the death of motor neurons in the cortex, brainstem, and spinal cord, resulting
in progressive muscle weakness and atrophy and death from respiratory failure usually
within 3 to 5 years of symptom onset (Brown, 1995).;