Search Results

You are looking at 1 - 2 of 2 items for

  • Author: Chalisa Louicharoen Cheepsunthorn x
Clear All Modify Search
Open access

Chalisa Louicharoen Cheepsunthorn and Issarang Nuchprayoon

Abstract

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an enzymopathy with high frequency in Southeast Asians. Phuan is a minority tribe in Thailand. The prevalence of G6PD deficiency and its molecular heterogeneity in this population is yet unknown.

Objectives: To characterize molecular heterogeneity of G6PD in Phuan people and investigate whether the heterogeneity of G6PD could be used to delineate the origin of Phuan people in Thailand.

Methods: Cord blood samples from 202 Phuan neonates were tested for G6PD deficiency using a G6PD activity assay. G6PD mutations were determined in G6PD deficient blood samples by polymerase chain reaction-restriction fragment length polymorphism analysis and sequencing.

Results: G6PD deficiency was found in 12 (12.2%) of 98 males and 8 (7.7%) of 104 females in the study population. Molecular analysis was performed on 12 males and 8 females to identify G6PD mutations. G6PD Viangchan (871G→A, 1311C→T)(25.0%) was the most dominant mutation followed by the G6PD Canton (1376G→T) (15.0%), G6PD Union (1360C→T) (10.0%), one case each of G6PD Kaiping (1388G→A) and G6PD Mediterranean (563C→T, 1311C) (5%), and eight G6PD deficient unidentified mutations.

Conclusions: G6PD deficiency in Phuan is highly frequent and G6PD Viangchan(871G→A, 1311C→T) is the most common mutation. Our study suggests that Phuans have coevolved with Thais, and were influenced by gene flow from Chinese and Indian mutations.

Open access

Ingfar Soontarawirat, Mallika Imwong, Charles J. Woodrow, Chalisa Louicharoen Cheepsunthorn, Nicholas P.J. Day, Richard Paul and Pratap Singhasivanon

Abstract

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.