The Viangchan-G6PD Mutation in Vietnamese-Kinh

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1 Kamla-Raj 2013 Int J Hum Genet, 13(2): (2013) The Viangchan-G6PD Mutation in Vietnamese-Kinh Nguyen Thi Hue 1*, Dang Thi Lan Anh 1, Nguyen Dien Thanh Giang 1 and Phan Ngo Hoang 2 1 School of Biotechnology, International University- VNU 2 School of Biology, University of science VNU KEYWORDS ARMS-PCR. Case/Control. G6PD Deficiency. Viangchan. Vietnamese ABSTRACT As the most common missense mutation cause of G6PD deficiency in Vietnamese, Viangchan [Val 291 Met] mutation can be used as the marker for development of the molecular diagnostic to diagnose this disease. To confirm Viangchan as the marker for diagnosis a case/control study is carried out. This study confirmed the role of Viangchan mutation in G6PD deficiency in Vietnamese and indicate the necessary of development of new molecular method for diagnosis of the diseases replace the fluorescence test recently as their limitation in identify G6PD patients. An AMRS-PCR was designed to screen Viangchan mutation in a 318 cases and 210 controls sample set. The result showed that Viangchan mutation occupied 26.7% in the population in this study, while in the G6PD deficient population it occupied 24%. The association analysis showed that the risk allele A in this mutation is strongly associated with G6PD deficiency in Vietnamese Kinh population (OR = 42.8; 95% CI [ ]; p<0.0001). The genotypes which contained risk alleles were also strongly associated with the disease (OR=22.4; 95% CI [ ]; p<0.0001). This study confirmed that the Viangchan is the most common causative mutation for G6PD deficiency in Vietnamese Kinh. Thus this mutation can be used as the indicator for diagnosis of G6PD in Vietnamese Kinh. INTRODUCTION * Correspondent author: nthue@hcmiu.edu.vn G6PD is a short for Glucose-6-phosphate dehydrogenase, an important enzyme that can be found throughout the body. This enzyme catalyzes the first step in pentose phosphate pathway, a primary anabolic pathway that utilizes the 6-carbon glucose to generate 5-carbon sugars and reducing equivalents in the form of NADPH. The role of G6PD is more important in red blood cells once it is the only NADPHproducing enzyme that is activated during oxidative stress. However, there are people who have less amount of G6PD than normal. This is called G6PD deficiency and is caused by a mutation in G6PD gene. There are more than 189 mutations in G6PD gene was found that related to G6PD deficiency on over the world (Minucci et al. 2012). Within found mutations 159 single missense mutations was listed and classified in classes based on their function (Minucci et al. 2012). Although there is a decrease in G6PD activity in most tissue in G6PD-deficient individual, this decreased activity is less marked than in red blood cells. With a lower amount of G6PD red blood cells can be damaged easily by the effects of reactive oxygen species. And then the damaged cells are likely to rupture and break down prematurely. There are many factors that can increase the levels of reactive oxygen species such as infections, certain drugs, and ingesting fava beans, which cause red blood cells to undergo hemolysis faster than the body can replace them. This loss of red blood cells causes the signs and symptoms of hemolytic anemia, which is a characteristic feature of glucose-6- phosphate dehydrogenase deficiency. Oxidative stress-induced hemolysis, favism, neonatal jaundice, and chronic non-spherocytic hemolytic anemia are four known clinical syndromes associated with G6PD deficiency. Based on the residual enzymatic activity and clinical manifestation, G6PD deficiency is classified into five classes: class I is associated with chronic nonspherocytic hemolytic anemia (CNSHA), class II is associated with acute hemolytic anemia (AHA) and has the residual enzyme activity (REA) less than 10%, class III is a moderate deficiency (REA 10-60%). Class IV has normal enzymatic activity and finally class V has an increased enzymatic activity with no clinical sequelae. It has been estimated that at least 400 million people carry a G6PD deficiency gene worldwide. Especially Africa, Southern Europe, the Middle East, South-East Asia and Oceania are areas with high prevalence. And the incident rate is different from area to area (Luzzatto 2006). Besides, different areas may have different types of dominant G6PD mutation. For instance, G6PD-Viangchan mutation is the most common variant in the Cambodian and Thai population while it is G6PD-Madihol mutation

2 86 NGUYEN THI HUE, DANG THI LAN ANH, NGUYEN DIEN THANH GIANG ET AL. in Myanmar population or in Malays population of Malaysia, G6PD-Viangchan and G6PD- Mediterranean are the main variants in G6PD deficient (Matsuoka et al. 2004; Matsuoka et al. 2005; Nuchprayoon et al. 2002; Yusoff et al. 2003). In Vietnam, a country with high incident rate of G6PD deficiency, G6PD Viangchan is also the most common variant (Hue et al. 2009, Matsuoka et al. 2007). Viangchan mutation is caused by a singlebase substitution which then leads to singleamino acid replacements. It occurs in exon 9 of G6PD gene. Once occur, nucleotide guanine (G) at the position is substituted by adenine (A). And the consequence of this substitution is that the amino acid Valine at the position 291 will change into Methionine (Val 291 Met). Base on the related phenotype, this mutation is classified into class 2 or 3 (WHO 1989) which causes severe deficiency or mild deficiency respectively. As the common of Viangchan in many populations particularly in the Southeast Asia, the wonder is whether this mutation is main cause of the G6DP deficiency? It is the common mutation in the population, but itself can cause of disease or need a combination with others or no harm as it may occur in healthy person? It is very necessary to determine again the role of Viangchan mutation in the relation to the disease. In addition, by screening the disease using fluorescence test with different cut off depended on different laboratories the patients may be missed due to the level of enzyme may change during the lifetime of red blood cells. Thus, this study is conducted to demonstrate the role of this mutation in related to the disease in Vietnamese Kinh by case/control study, in order to determine again the frequency of Viangchan mutation in Vietnamese population even cases and controls, particularly in Kinh majority ethnic and identify the relationship between this mutation with G6PD deficiency, and determine the role of this mutation in relation with the disease. Through this study the contribution of this mutation to the frequency of G6PD deficiency in Vietnamese Kinh is also determine. It is also very helpful in providing informative evidence for development a new molecular diagnostic test to detect the disease with more accurate. Subjects MATERIAL AND METHODS 317 cases/202 controls sample set was collected from newborns at Tu Du hospital- HCMC- Vietnam, since 2009 to This collection is under the ethnic approval at Tu Du hospital and NAFOSTED scientific board. The collected blood samples are dried blood spots on Walkman paper. All blood samples were collected and grouping after performing the test for G6PD deficiency using Fluorescence Spot test. The level of G6PD enzyme was measure two times; after born 1 day and 1 week to confirm the level of G6PD in each individual. The patient group is 317 newborns with G6PD level lower than 5.1 IU/gHg. The control group is 202 newborns with G6PD level higher than 5.3 IU/gHg. Within the cases 87% are male while in control group the ratio between male and female is nearly 1 (51% male and 49% female) (Table 1). As an X inherited disease the female cases is rarely in the population is reasonable. Table 1: The ratio male and female in relation to G6PD deficiency Total Control Case N=519 N=202 N=317 Male % 50.99% 87.07% Female % 49.01% 12.93% DNA Extraction DNA genomic is extracted from dried blood spots by the homemade phenol method which is optimized from the basic phenol method (Hue et al. 2012). Mutation Analysis To screening the Viangchan mutation in a case/control sample set, a set of three primers including one reverse primer IU30 (R-5 - GGTCGTCCAGGTACCCTTT) and two forward primers IU23 (F-5 -TGGCTTTCTCTCA GGTCAAGG) and IU24 (F-5 -TGGCTTT CTCTCAGGTCAAGA) were designed to PCR amplify a sequence from the position of 13,011 to 13,136 of G6PD gene where Viangchan muta-

3 THE VIANGCHAN-G6PD MUTATION 87 tion occurs. The forward primer IU23 and the reverse primer IU30 were used for detecting normal alleles while the forward primer IU24 and reverse primer IU30 were used for the detection of mutated alleles. PCR was performed in a 25µl reaction using the Toptaq master mix 2x, with a set of control primers and a set of specific primers. For one DNA sample, 2 PCR reactions were performed to detect the presence of 2 allele of the mutation, in which the reward primer is the same and the forward primer in each reaction is different in one 3 nucleotide. PCR cycling condition were as follows: 94 o C for 3mins, then 35 cycles of 94 o C for 30s, 64 o C for 30s, 72 o C for 1min; and then 72 o C for 10mins. PCR products were analysed on a 2% agarose gel containing ethidium bromide and the expected bands were visualized by ultraviolet illumination at 496bp for the control and 126bp for the specific allele. Each individual was examined with two assays to screening for two alleles. The result only read if the internal control band is present. The presence of two specific bands in two assays indicated the heterozygote in the genotype of the variant. The presence of only one band in one assay indicated the homozygote in the genotype. The homozygote can be mutant or wild type. As the X- linked the male having only one X chromosome so that the result of genotyping always is one band in one assay. The genotype can be count as homozygote for the present allele if necessary. Association Analysis The association between the risk allele and the genotypes with the diseases is analyzed using STATA software. Genotyping RESULTS A confirm heterozygous sample by sequencing was use as the positive control for the genotyping 2 allele of the mutation Viangchan. Figure 1 shows the typical genotyping results. By ARMS-PCR the genotype is clearly readable and the data was collected in Table 2 with the HWE is equilibrium (P=1.000) (Table 2). Table 2: Genotyping data and HWE testing for Viangchan mutation in the population Genotype/ Control Case HWE Allele (N=202) (N=317) Genotype GG 199 (98.51%) 237 (74.77%) P = GA 3 (1.49%) 6 (1.89%) (Exact AA 0 (0%) 74 (23.34%) test) Allele G 401 (99.26%) 480 (75.71%) A 3 (0.74%) 154 (24.29%) Three genotypes GG, GA and AA for the Viangchan SNP were collected in cases but the AA was not present in controls. While the A allele is 0.7% in the control it is 24% in cases. The genotype AA present in cases with 23% Fig. 1. A typical genotyping result for Viangchan mutation. The upper bands are the internal control bands from a HGH gene, at 496bp. The lower bands at 126bp are desired bands presented for specific allele of Viangchan mutation. IU23, IU24: primer for specific allele. GD: sample code

4 88 NGUYEN THI HUE, DANG THI LAN ANH, NGUYEN DIEN THANH GIANG ET AL. while it is not seen in control. A allele is the risk allele and it occupied 24% cases. If calculated in genotype including homozygote and heterozygote of risk allele AA and GA the risk genotypes occupied 23.34% % = 25.23%. Thus, the Viangchan mutation occupied about 25% G6PD cases in Vietnamese Kinh. Three control samples containing risk allele A, bring the frequency of individual containing risk allele in the population to 26.7%. Association between Viangchan Mutation and the G6PD Deficiency To confirm that the Viangchan mutation is really associated with the disease even there is some mistakes in the diagnostic the association analysis was performed in 317 case and 202 controls. The analysis was based on the allelic or genotypic. The result show that the allele A is strongly associated with G6PD deficiency when compare to G allele as the control for non G6PD deficiency (P<0.0001). The genotype AA compare to other genotypes (GG + GA) certainly showed the significant association with the disease (P<0.0001) as it is contain 2 risk alleles in the genotype. The wonder is whether the GA genotype with some mistake in diagnosis may end up with wrong association analysis. The comparison between group genotype contained mutated allele (AA+GA) to the GG-wildtype genotype showed the significant association also (P<0.0001). However, when compare the genotype GA only which contained 1 mutated allele with the GG-wildtype genotype the association with the diseases did not show (P=0.46) (Table 3). Based on this analysis, the heterozygous GA is the carrier only even contain the risk allele do not show the disease. However, this is not true, as the person with 1 chromosome mutated also having partial disease as lacking a part enzyme. As the risk allele is inherited with X chromosome thus the genotype for male and female Table 3: The association between mutated allele and homozygous mutated genotypes with the disease. Comparison Odds ratio 95% CI P value [G] 1 [A] < [GG] 1 [GA] [GG+GA] 1 [AA] < [GG] 1 [GA+AA] < may show the different association with the disease. To test this hypothesis the association analysis was performed for each type of genotype in the population. Using another way to analyse the data for more information about the association and clarify about the relationship between genotype and phenotype the group of male and female was analysed separated in Table 5 and Table 6. If analysing based on female only the data with homozygote of risk allele is not satisfied association analysis. However, the comparison between homozygote X G X G and X G X A showed the strong assocition with P= and the odd ratio at 5.6. This indicate the strong contribute of heterozygote genotype in female to the diseases. It is conflick to the previous result showed no association. The allelic analysis in this case again confirm the association with P= The power of the association analysis was also calculate for the such sample size and it reach 83% (Table 4). Divide study subjects into male and female group to analyse to see if there is any side effect in analysis in total as the risk allele link to X chromosome, male only have one X chromosome while female having two X chromosomes. Table 5 showed the result the female analysis while Table 5 showed the analysis for data from male only. The data showed that no male in control group having A allele. This confirmed the accurate of the test. And thus the association analysis showed the strong association between hemizygote Y X A with the disease in comparison with Y X G. The allelic analysis confirming the association with P< In this case, the Table 4: Analysis association of Viangchan mutation with G6PD deficiency in Vietnamese Kinh female Genotype/ Control Case Odds 95% CI P value Power allele (N=99) (N=41) ratio X A X A 0 (0%) 1(2.44%) X G X G 96 (96.97%) 34 (82.93%) X G X A 3 (3.03%) 6 (14.63%) G , ,13% A 3 8

5 THE VIANGCHAN-G6PD MUTATION 89 Table 5: Analysis association of Viangchan mutation with G6PD deficiency in Vietnamese Kinh male Genotype/ Control Case Odds 95% CI P value Power allele (N=103) (N=276) ratio Y X G 103 (50.99%) 203 (64.04%) - - < Y X A 0 (0%) 73 (23.03%) G < % if * =1 A 0 * 73 Table 6: Association analysis based on modified data alternate hemizygote to homozygote Genotype/ Control Case Odds 95% CI P value Power allele (N=202) (N=317) ratio AA 0 (0%) 74 (23.35%) GG 199 (98.52%) 237 (74.76%) GA 3 (1.48%) 6 (1.89%) G 401 (99.26%) 480 (75.71%) 29, < % A 3 (0.74%) 154 (24.29%) allele A no present in control and it no validate for calculation so that if the present of A is 1 in the control the power can be 100% have been analysed. In case consider the risk allele is located in the normal chromosome not in X chromosome that means consider the hemizygote in male like homozygote the data can be generated and analyses as seen in Table 6. The result showed that there is no genotype AA in the population and then the data is invalid for analysis for this genotype. When compare genotype wildtype GG and heterozygote mutant GA, there is no association P=0.55, and even the add ratio is 5.6 but the 95%CI is This indicated that this analysis is not reliable. This can be due the mistake in detection cases in testing disease by fluorescence test. However, the analysis based on allelic still showed the strongly association P< and odd ratio of 29 (95% CI ) The Relationship between Enzyme Level and Genotypes of Viangchan Mutation The level of G6PD enzyme in red blood cells from patients is measured by Fluorescence Spot test and the cut-off is 5.1IU/gHb. However, some samples with level of enzyme higher than 5.1 IU/gHb were also classified as the patient with G6PD deficiency based on another clearly clinical symptoms. In this case some of high enzyme level samples having Viangchan mutation. Thus it is clearly that the test is not very accurate in identify deficient cases. In another way, in the control group even with the level of en- zyme higher than 5.1IU/gHb some of them are having the Viangchan mutation. Samples with Viangchan mutation but having high level of enzyme are heterozygotes which only one chromosome containing risk allele while another one is normal. This again confirmed that the fluorescence test is not accurate in identifying partly deficient patient and particularly the heterozygote or the carriers. In more detail the result showed that within cases the homozygote of mutation AA or YA some time having higher level of enzyme compared to heterozygote while it should having lower enzyme level, such as 3.3 IU/gHb vs 1.8 IU/gHb in AA and AG; and 0.5 IU/gHb vs 0.1 IU/gHb in YA and YG (Table 7). Table 7: The relation between enzyme level and genotypes Genotype N 0 sample Range (IU/gHb) Control AA 0 - GA GG YA 0 - YG Case AA GA GG YA YG DISCUSSION In the previous study Viangchan had been showed as the most common mutation in Vietnam. It accounts for 36% and 9% of G6PD de-

6 90 NGUYEN THI HUE, DANG THI LAN ANH, NGUYEN DIEN THANH GIANG ET AL. ficiency in S tieng and Kinh ethnic group, respectively (Hue et al. 2009). Viangchan mutation was also found as the most common variant in another study which was carried out locally- only in Lam Dong province. In the population containing 88.9% of Kinh ethnic group and 11.1% of K Ho, Chauma, Nung, Tay minorities, G6PD deficiency was only found in Kinh and K Ho. And the Viangchan mutation appeared in both groups. The study also showed that in the K Ho group, only Viangchan mutation was found while in Kinh group, there were many other mutations. And when comparing the frequencies of different mutations in this group reported in this study, it can easily be found that the Viangchan mutation had the highest rate, 31.58%. Besides, this rate would be 44% when combining these groups together (Matsuoka et al. 2007). In the previous study within seven discovered mutation, the Viangchan was also demonstrated as the most common missense mutation within G6PD deficient patient in Vietnamese Kinh (Hue et al. 2013). Not only in Vietnam, G6PD Viangchan is also considered as a very common variant in Southeast Asia as well. There are many studies showed that this variant appeared with high ratio or even the most common variant in many countries around Southeast Asia. In Thailand, different studies have given different rate of G6PD Viangchan, however it is always in the top three of most common variants. For example, in 2002 a study carried by Nuchprayoon et. al. indicated that G6PD Viangchan is the most common variant in Thai population with the percentage of 54% (Nuchprayoon et al. 2002). While in 2005 in another study, Viangchan mutation was also found as the most common one, but with the ratio of 31.3% (Laosombat et al. 2005). Or recently, in 2011, Phompradit and his colleague have proved that this mutation is the second most common mutation with the rate of 19% (Phompradit et al. 2011). Together with Vietnam and Thailand, Cambodia is another country where Viangchan mutation in also consider as the most common mutation with a very high rate: 97.9% in one study and 82.4% in another (Louicharoen and Nuchprayoon 2005; Matsuoka et al. 2005). In addition, this mutation also appeared in the Malaysian Malays population with highest percentage: 37.2% (Yusoff et al. 2003). This study confirmed a relationship between Viangchan mutation and G6PD deficiency disease in Vietnamese Kinh population. Like other countries in South East Asia, Viangchan mutation was found in Vietnamese population with a quite high frequency 26% in this study. In comparing with the other studies about G6PD deficiency in Vietnam, similar results were also reported. For example, in a study in Lam Dong province many different G6PD mutations were found in Vietnamese population such as G6PD Canton, G6PD Kaiping, G6PD Gaohe, G6PD Quing Yuan, and G6PD Union, etc. however Viangchan mutation is the most dominant one with the frequency of 32% (Matsuoka et al. 2007). Even though the frequency in previous studies is quite different from this study and each other but the Viangchan is always the most common mutation in Vietnamese Kinh population. The differences in frequency may due to the sample size and the selected sample group. Two different frequency of Viangchan mutation had been found in Vietnamese Kinh population in the previous studies are 9% (Hue et al. 2009) and 43% (Hue et al. 2013) and it was the most common mutation in those studies. Not only in Vietnam, Viangchan mutation was also found as the most common variant in Laos (Iwai et al. 2001), Cambodia (Matsuoka et al. 2005), Thailand (Nuchprayoon et al. 2002), and Malaysia Malays (Yusoff et al. 2003). However, in comparing with these countries, the frequency of Viangchan mutation in Vietnam is lower than in Cambodia and Thailand; and higher than in Malaysia. Specifically, the frequency of Viangchan mutation in Cambodia is 97.9%, in Thailand is 54%, and Malays population of Malaysia is 28.7%. From these data it can be hypothesized that there was a strong historical connection between these populations. The association of the risk allele with the disease is clearly strong with p< and very high odd ratio. However, due to some reasons of collection sample or diagnostic test the level of enzyme in relation to the presence of mutation is not clear. The heterozygote of Viangchan mutation do not show the association with disease when compare to the homzygote wildtype. This indicated that the heterozygote cases in the population is so low or the detection of current method for the heterozygotes or carriers. This study has confirmed again that Viangchan mutation is a recessive mutation. Most of cases are male as the risk allele is linked to X chromosome. When comparing G6PD deficient status

7 THE VIANGCHAN-G6PD MUTATION 91 tested by Fluorescence spot test and the genotypes of Viangchan, the result showed that three sample which was classified as healthy sample by non-deficient sample was found to have heterozygous mutant genotype in this study. This indicates that the heterozygous individual can be easily missed because with only one normal allele the heterozygous individual still can produce a certain amount of G6PD, which does not belong to deficient range. And thus, this person seems not to be affected by having only one risk allele. From this point, it can be recognized that first, the heterozygous genotype is difficult to be detected correctly by using method of detection at protein level. These things are very important in term of diagnosis and epidemiology of disease. While the heterozygous individuals, also called the carriers, usually do not have any symptom they normally considered themselves as healthy. And when they have children they will pass the mutation to their children unconsciously. This will increase the percentage of this mutation, and the possibility of having G6PD deficiency in Vietnamese population. Due to this reason, it is necessary to develop a molecular diagnosis method, which can also detect a heterozygous mutant genotype correctly. Then, this will help a lot in controlling and limiting the spread of G6PD deficiency disease. Viangchan mutation in this study have been demonstrated as the common causative mutation of G6PD deficiency in Vietnamese Kinh, thus it can be used as the indicator for diagnosis of G6PD deficiency for Vietnamese Kinh. When detection of Viangchan only a molecular test can detect at least 24% cases. Thus, another mutation which also common need also be identified and confirmed as the indicator for a future molecular test. The Viangchan is not only common in Vietnamese but also common in other population in southest Asian such as campuchia (Kim et al. 2011). Thus the test based on Viangchan can be used not only for Vietnamese but also for other populations. CONCLUSION The strongly association between Viangchan mutation and G6PD deficiency in Vietnamese Kinh was proved. Beside the strong association of hemizygote YX A with the disease the heterozygote (X A X A ) also show the strong association with the disease. As one of most common causative mutation of G6PD deficiency in Vietnamese Kinh population the Viangchan mutation can be used as a marker for development of molecular diagnostic test for G6PD deficiency for Vietnamese Kinh population to overcome the missing partial deficient patients or carriers. ACKNOWLEDGMENTS The authors would like to thank staffs at Tu Du hospital for recruitment of patients for this study. Thanks to all patients involved in this study. This study is funded by National Foundation Science and Technology Development (NAFOSTED) under project The ethnic approval for this sample collection is approved by Tu Du hospital- HCMC-Vietnam. REFERENCES Hue NT, Charlieu JP, Chau TT, Day N, Farrar JJ, Hien TT, Dunstan SJ Glucose-6-phosphate dehydrogenase (G6PD) mutations and haemoglobinuria syndrome in the Vietnamese population. Malar J, 8: 152. Hue NT, Anh DTL, Trinh HLT, Hoang PN Common mutations in G6PD of Vietnamese-Kinh deficient patients. African Journal of Biotechnology, 12: Hue NT, Chan NDH, Phong PT, Linh NTT, Giang ND Extraction of human genomic DNA from dried blood spots and hairs roots. International Journal of Bioscience, Biochemistry and Bioinformatics, 2: Iwai K, Hirono A, Matsuoka H, Kawamoto F, Horie T et al Distribution of glucose-6-phosphate dehydrogenase mutations in Southeast Asia. Hum Genet, 108: Kim S, Nguon C, Guillard B, Duong S, Chy S, et al Performance of the CareStart G6PD deficiency screening test, a point-of-care diagnostic for primaquine therapy screening. PloS one, 6: e Laosombat V, Sattayasevana B, Janejindamai W, Viprakasit V, Shirakawa T, Nishiyama K, Matsuo M Molecular heterogeneity of glucose-6-phosphate dehydrogenase (G6PD) variants in the south of Thailand and identification of a novel variant (G6PD Songklanagarind). Blood Cells Mol Dis, 34: Louicharoen C, Nuchprayoon I G6PD Viangchan (871G>A) is the most common G6PD-deficient variant in the Cambodian population. J Hum Genet, 50: Luzzatto L Glucose 6-phosphate dehydrogenase deficiency: From genotype to phenotype. Haematologica, 91: Matsuoka H, Wang J, Hirai M, Arai M, Yoshida S, Kobayashi T, Jalloh A, Lin K, Kawamoto F Glucose-6-phosphate dehydrogenase (G6PD) mutations in Myanmar: G6PD Mahidol (487G>A) is the most common variant in the Myanmar population. J Hum Genet, 49: Matsuoka H, Thuan DT, van Thien H, Kanbe T, Jalloh A, Hirai M, Arai M, Dung NT, Kawamoto F Seven

8 92 NGUYEN THI HUE, DANG THI LAN ANH, NGUYEN DIEN THANH GIANG ET AL. different glucose-6-phosphate dehydrogenase variants including a new variant distributed in Lam Dong Province in southern Vietnam. Acta Med Okayama, 61: Matsuoka H, Nguon C, Kanbe T, Jalloh A, Sato H, Yoshida S, Hirai M, Arai M, Socheat D, Kawamoto F Glucose- 6-phosphate dehydrogenase (G6PD) mutations in Cambodia: G6PD Viangchan (871G>A) is the most common variant in the Cambodian population. J Hum Genet, 50: Minucci A, Moradkhani K, Hwang MJ, Zuppi C, Giardina B, Capoluongo E Glucose-6-phosphate dehydrogenase (G6PD) mutations database: Review of the old and update of the new mutations. Blood Cells Mol Dis, 48: Nuchprayoon I, Sanpavat S, Nuchprayoon S Glucose- 6-phosphate dehydrogenase (G6PD) mutations in Thailand: G6PD Viangchan (871G>A) is the most common deficiency variant in the Thai population. Hum Mutat, 19: 185. Phompradit P, Kuesap J, Chaijaroenkul W, Rueangweerayut R, Hongkaew Y, Yamnuan R, Na-Bangchang K Prevalence and distribution of glucose-6-phosphate dehydrogenase (G6PD) variants in Thai and Burmese populations in malaria endemic areas of Thailand. Malar J, 10: 368. WHO Glucose-6-phosphate dehydrogenase deficiency. Bulletin of World Health Organization, 67: Yusoff NM, Shirakawa T, Nishiyama K, Ee CK, Isa MN, Matsuo M G6PD Viangchan and G6PD Mediterranean are the main variants in G6PD deficiency in the Malay population of Malaysia. Southeast Asian J Trop Med Public Health, 34 Suppl 3: