Amyotrophic Lateral Sclerosis 3
Description
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).
For a phenotypic description and a discussion of genetic heterogeneity of amyotrophic lateral sclerosis (ALS), see ALS1 (105400).
MappingHand et al. (2002) performed a genome scan in a large European family (pedigree Fr017) in which at least 20 members had autosomal dominant, adult-onset ALS unlinked to chromosome 21. They found linkage of the disorder in this family to chromosome 18q21 (maximum lod score of 4.5) within a 7.5-cM, 8-Mb region flanked by markers D18S846 and D18S1109. The authors stated that the familial ALS locus on chromosome 18 represents the most common form of familial ALS.