We investigated the segregation of the copper chaperone for the superoxide dismutase (CCS) gene in two Italian families with amyotrophic lateral sclerosis lacking the mutations in superoxide dismutase 1 gene. We analyzed a total of 56 individuals; six people were affected. Diagnoses were made using the El Escorial criteria. The results of our study provide no evidence of a linkage between markers flanking the CCS gene and familial amyotrophic lateral sclerosis (FALS) in these FALS kindreds.