Molecular Epidemiology of G6PD Genotypes in Different Ethnic Groups Residing in Saharan and Sahelian Zones of Mauritania

Abstract

Plasmodium vivax malaria is endemic in Mauritania. Individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency may develop acute hemolytic anemia when exposed to 8-aminoquinoline antimalarial drugs, which are indispensable for a complete cure. The prevalence of G6PD allelic variants was assessed in different ethno-linguistic groups present in Mauritania. A total of 996 blood samples (447 males and 549 females; 499 white Moors and 497 individuals of black African ancestry) were collected from febrile patients in 6 different study sites: Aleg, Atar, Kiffa, Kobeni, Nouakchott, and Rosso. The presence of the African-type G6PD A- (G202A, A376G, A542T, G680T, and T968C mutations) and the Mediterranean-type G6PD B- (C563T) variants was assessed by PCR followed by restriction fragment length polymorphism and/or DNA sequencing. The prevalence of African-type G6PD A- genotype was 3.6% (36/996), with 6.3% (28/447) of hemizygote (A-) males and 1.5% (8/549) of homozygous (A-A-) females. Forty of 549 (7.3%) women were heterozygous (AA-). The following genotypes were observed among hemizygous men and/or homozygous women: A376G/G202A (22/996; 2.2%), A376G/T968C Betica-Selma (12/996; 1.2%), and A376G/A542T Santamaria (2/996; 0.2%). The Mediterranean-type G6PD B- genotype was not observed. The prevalence rates of G6PD A- genotype in male (10/243; 4.1%) and heterozygous female (6/256; 2.3%) white Moors were lower (p < 0.05) than those of males (18/204; 8.8%) and heterozygous females (34/293; 11.6%) of black African ancestry. There were only a few homozygous women among both white Moors (3/256; 1.2%) and those of black African ancestry (5/293; 1.7%). The prevalence of G6PD deficiency in Mauritania was comparable to that of neighboring countries in the Maghreb. Because of the purportedly close ethnic ties between the Mauritanian white Moors and the peoples in the Maghreb, further investigations on the possible existence of the Mediterranean-type allele are required. Moreover, a surveillance system of G6PD phenotype and/or genotype screening is warranted to establish and monitor a population-based prevalence of G6PD deficiency.

Performance of a Commercial Multiplex Allele-Specific Polymerase Chain Reaction Kit to Genotype African-Type Glucose-6-Phosphate Dehydrogenase Deficiency

“…Our preliminary study using PCR-RFLP showed that 6.3% of Mauritanian males of both Arab-Berber and black African ancestries have the African-type G6PD A 2 genotype (G6PD A 2(202) , G6PD A 2 Santamaria, and G6PD A 2 Betica-Selma), whereas the Mediterranean-type genotype was not observed. 42 In Mali and Senegal, two countries that share a common border with Mauritania to the east and south, the African-type G6PD A 2 genotype has been reported in 2.2% to 10% of males. 43,48,49 In the countries north of Mauritania, the prevalence of a G6PD enzyme deficiency in the male population has been reported to be 3.2% in Algeria, mostly because of autochthonous variants predominated by the Kabyle type, but also resulting from the Mediterranean-type genotype as well as the African-type A 2 in a minority of persons with black African ancestry.…”

“…PCR was 100% successful in two other PCR plates, and genotyping by PCR-RFLP and sequencing was successful with the same samples as those in the first PCR plate, ruling out template quality as the possible cause of failure. 42 Moreover, the earlier 2013 protocol (version 1.3) of the manufacturer recommended an annealing temperature of 60 C. Indeed, for all samples in two PCR plates, lowering the annealing temperature to 60 C resulted in clearly visible bands in agarose gel electrophoresis. This observation implies that some test runs with control samples are required in each laboratory before PCR amplification in PCR plates is performed.…”

“…The PCR-RFLP protocol used in this study has been described in detail elsewhere. 42 Briefly, several fragments of exons of G6PD spanning nucleotides 202, 376, 542, 563, 680, and 968 were amplified using the PCR protocols developed by Carter et al 43 (for African-type G6PD genotypes) and Ezz El-Deen et al 44 (for the Mediterranean type G6PD genotype).…”

“…PCR was performed as described in the PCR-RFLP protocol to amplify the fragment of the G6PD exon spanning the nucleotide with a discordant result. 42 Sequencing, as well as purification of PCR products, was outsourced to Biofidal Themis (Vaulx-en-Velin, France). Each fragment was sequenced from both 5'-and 3'-ends.…”

“…A total of 996 samples were analyzed initially using PCR-RFLP. 42 Of these, 279 were selected by matching each sample with a mutant genotype (n 5 76) to two to three samples with a wild-type genotype on the basis of gender, age, and study site.…”