BACKGROUND: G6PD deficiency is common in malaria endemic regions and is 
estimated to affect more than 400 million people worldwide. Treatment of malaria 
patients with the anti-malarial drug primaquine or other 8-aminoquinolines may 
be associated with potential haemolytic anaemia. The aim of the present study 
was to investigate the prevalence of G6PD variants in Thai population who 
resided in malaria endemic areas (western, northern, north-eastern, southern, 
eastern and central regions) of Thailand, as well as the Burmese population who 
resided in areas along the Thai-Myanmar border.
METHODS: The ten common G6PD variants were investigated in dried blood spot 
samples collected from 317 Thai (84 males, 233 females) and 183 Burmese (11 
males, 172 females) populations residing in malaria endemic areas of Thailand 
using PCR-RFLP method.
RESULTS: Four and seven G6PD variants were observed in samples collected from 
Burmese and Thai population, with prevalence of 6.6% (21/317) and 14.2% 
(26/183), respectively. Almost all (96.2%) of G6PD mutation samples collected 
from Burmese population carried G6PD Mahidol variant; only one sample (3.8%) 
carried G6PD Kaiping variant. For the Thai population, G6PD Mahidol (8/21: 
38.1%) was the most common variant detected, followed by G6PD Viangchan (4/21: 
19.0%), G6PD Chinese 4 (3/21: 14.3%), G6PD Canton (2/21: 9.5%), G6PD Union 
(2/21: 9.5%), G6PD Kaiping (1/21: 4.8%), and G6PD Gaohe (1/21: 4.8%). No G6PD 
Chinese 3, Chinese 5 and Coimbra variants were found. With this limited sample 
size, there appeared to be variation in G6PD mutation variants in samples 
obtained from Thai population in different regions particularly in the western 
region.
CONCLUSIONS: Results indicate difference in the prevalence and distribution of 
G6PD gene variants among the Thai and Burmese populations in different malaria 
endemic areas. Dosage regimen of primaquine for treatment of both Plasmodium 
falciparum and Plasmodium vivax malaria may need to be optimized, based on 
endemic areas with supporting data on G6PD variants. Larger sample size from 
different malaria endemic is required to obtain accurate genetic mapping of G6PD 
variants in Burmese and Thai population residing in malaria endemic areas of 
Thailand.