G6PD Haplotypes Spanning Xq28 from F8C to Red/Green Color Vision

Filosa, Stefania; Calabrò, Viola; Lania, Gabriella; Vulliamy, Tom; Brancati, C.; Tagarelli, Antonio; Luzzatto, Lucio; Martini, Giuseppe

doi:10.1006/geno.1993.1276

Cited by 47 publications

(33 citation statements)

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“…303800) that is responsible for green color blindness is located within this region (350 kb proximal to G6PD). A study by Filosa et al (1993) demonstrated that in a region of Calabria that bears the Mediterranean-type G6PD deficiency allele (G6PD med coding site 563 C / T), all individuals with the 563 C / T mutation (n ¼ 7) were also deutan (green) color-blind on the basis of a visual acuity test. This suggests that in this population a chromosome that carried a G6PD med allele also harbored a mutation causing a clinical condition of deutan color blindness.…”

Section: Discussionmentioning

confidence: 99%

The Extent of Linkage Disequilibrium Caused by Selection on G6PD in Humans

et al. 2005

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The gene coding for glucose-6-phosphate dehydrogenase (G6PD) is subject to positive selection by malaria in some human populations. The G6PD Aÿ allele, which is common in sub-Saharan Africa, is associated with deficient enzyme activity and protection from severe malaria. To delimit the impact of selection on patterns of linkage disequilibrium (LD) and nucleotide diversity, we resequenced 5.1 kb at G6PD and 2-3 kb at each of eight loci in a 2.5-Mb region roughly centered on G6PD in a diverse sub-Saharan African panel of 51 unrelated men (including 20 G6PD Aÿ, 11 G6PD A1, and 20 G6PD B chromosomes). The signature of selection is evident in the absence of genetic variation at G6PD and at three neighboring loci within 0.9 Mb from G6PD among all individuals bearing G6PD Aÿ alleles. A genomic region of 1.6 Mb around G6PD was characterized by long-range LD associated with the Aÿ alleles. These patterns of nucleotide variability and LD suggest that G6PD Aÿ is younger than previous age estimates and has increased in frequency in subSaharan Africa due to strong selection (0.1 , s , 0.2). These results also show that selection can lead to nonrandom associations among SNPs over great physical and genetic distances, even in African populations.

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Section: Discussionmentioning

confidence: 99%

The Extent of Linkage Disequilibrium Caused by Selection on G6PD in Humans

et al. 2005

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“…The distance between the opsin genes and G6PD is approximately 300 kb [10,11]. Consistent with the strong linkage disequilibrium between the genes, a number of previous reports have found phenotypic or genotypic evidence of haplotypic association at the opsin (OPN1LW/OPN1MW) and G6PD loci [12,13].…”

Section: Amentioning

confidence: 61%

“…Evidence for linkage between G6PD deficiency and color blindness has been found in a number of locations, including Israel [16], the United States of America [17], and Sardinia [12,18,19]. However, many studies have revealed no association (positive or negative), presumably because the linkage disequilibrium is weak (so recombination breaks down any relationships) or because the phenotypes have more than one common cause in the studied population.…”

Section: Discussionmentioning

confidence: 99%

Exploring the association between glucose-6-phosphate dehydrogenase deficiency and color blindness in Southeast Asia

et al. 2017

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Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency poses problems for the treatment of Plasmodium vivax malaria, as the 8-aminoquinolines, used to eliminate liver hypnozoites, cause hemolysis in G6PD-deficient individuals. G6PD deficiency is an X-linked disorder that can be linked to other conditions determined by genes located nearby on the Xq28 band of the X chromosome, including red-green color blindness. A Karen population has undergone recent positive selection for G6PD deficiency with extended long-range haplotypes around G6PD. Objectives: To determine the association between G6PD deficiency and color blindness in a Karen population that lives in an area endemic for P. vivax and that is already known to display long-range haplotypes around G6PD because of the recent positive selection of the Mahidol G6PD deficiency allele. Method: We examined the phenotypic association between G6PD deficiency and color blindness. Results: Of 186 male participants successfully assessed for color blindness using the Ishihara 38 plates test, 10 (5.4%) were red-green color blind, while 1 individual was totally color blind. There was a nonsignificant trend toward negative association (repulsion) between G6PD deficiency and red-green color blindness; 34/35 individuals with the Mahidol variant of G6PD deficiency had normal vision, while 9 of the 10 red-green color blind individuals were G6PD normal. A single individual had both conditions. Conclusions: Despite the long-range haplotype associated with G6PD deficiency in this population, color blindness is not informative in terms of predicting G6PD deficiency in this population. The most likely explanation is that there are multiple genetic causes of red-green color blindness.

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“…[ Table- 5]. Few respondents were already using glasses but majority did not use recommended glasses.…”

Section: Recording Of Color Visionmentioning

confidence: 99%