Novel mutation in the ALS2 gene in juvenile amyotrophic lateral sclerosis.

We present a 32-year-old Turkish male with juvenile amyotrophic lateral sclerosis 2 and a previously unrecognized homozygous deletion in exon 4 of the ALS2 gene (553delA). Disease progression is more rapid than in the ALS2 phenotype cases described to date. The patient's consanguineous parents carry the mutation in the heterozygous state as do his two unaffected brothers.