THE IDENTIFICATION OF MOLECULAR VARIANTS OF THE ENZYME GLUCOSE-6-PHOSPHATE-DEHYDROGENASE BY THE POLYMERASE CHAIN-REACTION TECHNIQUE

BACKGROUND: An assessment of the usefulness of polymerase chain reacti on (PCR) in the identification of the most frequent molecular variants of the glucose-6-phosphate dehydrogenase (G6PD) in Spain: G6PD A-, G6 PD Mediterranean and G6PD Seattle through the screening of the mutatio ns: 376 A-->G; 202 G-->A; 680 G-->T; 968 T-->C; 563 C-->T and 844 G--> C. METHODS: Three groups of patients have been studied: 1) males (40 c ases); 2) relatives from the preceding group (31 cases: 7 males and 24 females), and 3) samples classified according to their fast electroph oretic mobility as G6PD A-(17 cases). The method used has been the PCR followed by digestion with specific restriction endonucleases. RESULT S: Group 1: 23 out of 40 samples (57%), were identified as G6PD Med563 T variant (8 cases), G6PD A-376G/202A (13 cases) and G6PD Seattle844C (2 cases). Group 2: The study of relatives from 13 of the 23 identifie d samples allowed the study of additional 31 samples (7 males, 24 fema les): hemizygous G6PD Med563T (3 cases), heterozygous Gd(B)/Gd Med563T (5 cases), hemizygous G6PD A-376G/202A (4 cases), heterozygous Gd(B)/ Gd A-376G/202A (11 cases), heterozygous Gd(B)/Gd Seattles844C (1 case) and normal females (7 cases). Group 3: In all electrophoretically fas t samples classified as G6PD A-was detected the 376 A-->G mutation (ch aracteristic of G6PD A+). In 15 of these cases a second mutation was f ound at nucleotide 202 G-->A (G6PD A-376G/202A); and in two, at nucleo tide 968 T-->C (G6PD A-376G/968C). CONCLUSIONS: The PCR method is fast and simple enough to allow the identification of known G6PD deficient variant, avoiding the need of its molecular characterization, which i s more cumbersome and time consuming. In addition, the PCR is a very u seful tool for demonstrating the carrier condition of G6PD deficiency in females with enzyme activity within normal range.