Refined mapping and characterization of the recessive familial amyotrophic lateral sclerosis locus (ALS2) on chromosome 2q33.

Amyotrophic lateral sclerosis (ALS) is a progressive degenerative neuromuscular disease that shows familial, autosomal dominant inheritance in 10%-15% of cases. Previous genetic analysis of one large family linked a recessive form of familial ALS (FALS-AR type 3) to the chromosome 2q33-35 region. Using additional polymorphic markers, we have narrowed the size of the linked region to approximately 1.7 cM by linkage and haplotype analysis. We have also established a yeast artificial chromosome contig across the locus that covers an approximate physical distance of 3 million bases. Based on this contig, genes and expressed sequences that map near the 2q33 region have been examined to determine whether they are located within this ALS2 candidate locus. Five identified genes and 34 expressed sequence tags map within the region defined by crossover analysis and merit further consideration as candidate genes for this disease.