G6PD Canton a common deficient variant in South East Asia caused by a 459 Arg→Leu mutation

Abstract

G6PD Canton is one of the most common deficient variants in Orientals, reaching a gene frequency of 1.7% in Southern China (1). To identify the molecular lesion in G6PD Canton we have sequenced the G6PD gene from an affected individual by PCR amplification of exons followed by M13 cloning and dideoxynucleotide sequencing as described previously (2). The entire coding sequence was determined. Only one base difference from the wild type sequence G6PD B (3) was found; this was a G— T change at position 1376 resulting in the substitution of leucine for arginine at amino acid position 459. The change of basic to uncharged amino acid is consistent with the electrophoretic fast mobility of G6PD Canton. This arginine residue is not conserved in G6PD molecules from yeast and drosophila but it lies between two blocks of highly conserved amino acids (4, 5).