A SOD1 gene mutation in a patient with slowly progressing familial ALS.

We report a new missense mutation (Gly12Arg) [corrected] in exon 1 of the Cu/Zn superoxide dismutase (SOD1) gene in a 67-year-old patient with familial ALS (FALS). The clinical course showed an unusually slow progression. The enzymatic activity of the mutated SOD1 was 80% of normal. At the molecular level, the Gly12Arg [corrected] mutation occurs in a region outside the active site and may lead to local distortion strain in the protein structure.