A novel mutation of SOD-1 (Gly 108 Val) in familial amyotrophic lateral sclerosis

A novel mutation of the SOD-1 gene which encodes the enzyme copper-zinc superoxide dismutase was identified in a family manifesting amyotrophic lateral sclerosis (ALS) in three generations. The mutation is a heterozygote point mutation in exon 4, codon 108 (GGA to GTA), predicting the substitution of valine for glycine. The mutation creates a new restriction site for the endonuclease AccI. The mutation was demonstrated in two affected members of the family, who show features of autosomal dominant inheritance of ALS, but variable age at onset ranging from 48 to 72 years. Over 30 different mutations of SOD-1 have now been identified in families with ALS. The definition of the different mutations causing human disease may allow further investigation of their pathogenicity in transgenic animal models, and also offers insight into the variable phenotypic disease expression both within and between genotypes.