Identification of an A4V SOD1 mutation in a Chinese patient with amyotrophic lateral sclerosis without the A4V founder effect common in North America.

We identified a missense alanine to valine mutation at codon 4 (A4V) in the Cu/Zn superoxide dismutase (SOD1) gene in a 51-year-old male of Chinese origin with familial amyotrophic lateral sclerosis (ALS). The patient displayed a typical A4V-related phenotype that included rapid progression and predominant lower motor neuron involvement. This patient is the first such carrier reported outside Caucasian ALS patients, despite the fact that A4V mutations account for up to 50% of all SOD1 mutations in North America. Further SNP analyses showed that the A4V patient of Chinese origin did not share the common founder effect observed in North America.