OBJECTIVETo identify the mutation of Cu/Zn superoxide dismutase(SOD1) gene in an amyotrophic lateral sclerosis (ALS) family with unique phenotype.

METHODSFive exons of SOD1 gene were amplified by PCR. The differences of these products were analyzed by PCR-single strand conformation polymorphism and visualized by silver staining.

RESULTSAbnormal bands were found in exons 2 and 5 of SOD1 gene in several familial members. DNA sequence analysis verified that a base pair insertion occurred in the codon area of exon 2 and in the intron area of exon 5. And the insertion mutation of exon 2 led to a frameshift mutation and premature stop. It is a new type of SOD1 mutation which may be associated with familial amyotrophic lateral sclerosis.

CONCLUSIONInsertion mutation of exon 2 may be responsible for the disease of an ALS family in Chongqing.