Study of Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency and Genotype Polymorphism of G6PD B and G6PD (A+/A-) in Patients Treated for Plasmodium vivax Malaria in a Tertiary Care Hospital in North East India

Abstract

Introduction Glucose-6-phosphate dehydrogenase (G6PD) enzyme deficiency is the most common enzymopathy in humans, and its distribution has been historically described to be closely associated with that of malaria. North East India provides optimal conditions for transmission of malaria and bears a considerable burden of Plasmodium vivax (P. vivax) malaria. Primaquine, a mainstay in the treatment of vivax malaria, may trigger episodes of acute hemolysis in patients with G6PD deficiency. The present study sought to delineate the frequency and genotypes of G6PD deficiency among patients suffering from vivax malaria infections. Methods Blood specimens from 80 individuals diagnosed with vivax malaria underwent enzyme assay for G6PD deficiency. Samples with deficient phenotype underwent isolation of DNA using a genomic DNA isolation kit (Qiagen India Pvt. Ltd., New Delhi, India). The genomic DNA underwent amplification, serial denaturation, annealing, extension, final extension followed by digestion with restriction endonucleases Nla III and Fok I. The digested products were subjected to horizontal agarose electrophoresis for the separation of digested fragments. Samples without nucleotide 376 adenine→guanine (A→G) mutation were classified as G6PD B. Those with the mutation were further classified into G6PD A(+) and G6PD A(-) based on the presence of Nla III site. Results Twenty-seven out of 80 individuals (33.75%) with P. vivax malaria were found to have G6PD deficiency, of which a majority (n=24) had G6PD B genotype. Three individuals had Asparagine→Aspartic Acid mutation at position 376 (A→G), of which G6PD A(+) and G6PD A(-) were present in two and one cases, respectively. Conclusion G6PD deficiency was noted in about a third of patients with vivax malaria. Since primaquine therapy is contraindicated in this group of patients, there is a rationale for looking into screening patients with vivax malaria from the region prior to primaquine therapy. Further large scale studies may substantiate this and help in better genotypic and geographic characterization of G6PD deficiency in the region.

Keywords: g6pd a(+); g6pd a(-); g6pd b; g6pd genotype; glucose-6-phosphate-dehydrogenase deficiency (g6pd); malaria; north east india; plasmodium vivax.

Figure 1. Frequency of G6PD deficiency and G6PD B and G6PD (A+/A-) genotypes

G6PD: glucose-6-phosphate-dehydrogenase

Figure 2. Agarose gel electrophoresis showing Fok I restriction site indicating 376 A→G mutation (white arrow)

bp: base pair

Figure 3. Agarose gel electrophoresis showing FoK I and Nla III restriction site indicating 376 A→G mutation (white arrowhead) and G6PD A(-) 202A/376G mutation (white arrow)

bp: base pair