Objective To determine whether the gene related to an amyotrophic lateral sclerosis family in Chongqing is linked to chromosome 21q microsatellite marker D21S223 by genetic linkage analysis. Methods D21S223 polymorphims were analyzed by polymerase chain reaction amplification and denaturing polyacrylamide gel electrophoresis. Linkage analysis was performed by GeneHunter soft package(version 2.0). Results A peak 2-point Lod score of 3.06 (θ=3.06) was obtained, suggesting that this familial amyotrophic latera...