G6PD FERRARA-I HAS THE SAME 2 MUTATIONS AS G6PD A(-) BUT A DISTINCT BIOCHEMICAL PHENOTYPE

The cloning and sequencing of the normal glucose-6-phosphate dehydroge nase (G6PD) gene has led to the study of the molecular defects that de termine enzymatic variants. In this paper, we describe the mutations r esponsible for the Ferrara I variant in an Italian man with a family h istory of favism, from the Po delta. Nucleotide sequencing of this var iant showed a G-->A mutation at nucleotide 202 in exon IV causing a Va l-->Met amino acid exchange, and a second A-->G mutation at nucleotide 376 in exon V causing an Asn-->Asp amino acid substitution. Although on the basis of its biochemical properties this variant was classified as G6PD Ferrara I, it has the same two mutations as G6PD A(-), which is common in American and African blacks, and as the sporadic Italian G6PD Matera. The mutation at nucleotide 202 was confirmed by NlaIII di gestion of a polymerase chain reaction amplified DNA fragment spanning 109bp of exon IV. The 109-bp mutated amplified sequence is not distin guishable from the normal sequence in single strand conformation polym orphism analysis.