Characterization of G6PD deficiency in southern Croatia: description of a new variant, G6PD Split

Molecular Characterization of Glucose-6-phosphate Dehydrogenase Deficiency in Families from the Republic of Macedonia and Genotype-phenotype Correlation

Introduction:

Glucose-6-phospahte dehydrogenase deficiency (G6PD) is one of the most common inherited disorders affecting around 400 million people worldwide. Molecular analysis of the G6PD gene identified more than 140 distinct mutations, the majority being single base missense mutations. G6PD Mediterranean is the most common variant found in populations of the Mediterranean area.

Aim:

The aim of our study was to perform molecular characterization of G6PD deficiency in families from the Republic of Macedonia and correlate the findings to disease phenotype.

Patients and methods:

Six patients and seven other family members were selected for genetic characterization, the selection procedure involved clinical evaluation and G6PD quantitative testing. All patients were first screened for the Mediterranean mutation, and subsequently for the Seattle mutation. Mutations were detected using PCR amplification and appropriate restriction endonuclease cleavage.

Results:

Four hemizygote and 3 heterozygous carriers for G6PD Mediterranean were detected. All G6PD deficient patients from this group showed clinical picture of hemolysis, and in 66.6% neonatal jaundice was confirmed based on history data. To our knowledge, this is the first study concerned with molecular aspects of the G6PD deficiency in R. Macedonia.

Conclusion:

This study represents a step towards a more comprehensive genetic evaluation in our population and better understanding of the health issues involved.

Glucose-6-phosphate dehydrogenase (G6PD) mutations database: review of the "old" and update of the new mutations

In the present paper we have updated the G6PD mutations database, including all the last discovered G6PD genetic variants. We underline that the last database has been published by Vulliamy et al. [1] who analytically reported 140 G6PD mutations: along with Vulliamy's database, there are two main sites, such as http://202.120.189.88/mutdb/ and www.LOVD.nl/MR, where almost all G6PD mutations can be found. Compared to the previous mutation reports, in our paper we have included for each mutation some additional information, such as: the secondary structure and the enzyme 3D position involving by mutation, the creation or abolition of a restriction site (with the enzyme involved) and the conservation score associated with each amino acid position. The mutations reported in the present tab have been divided according to the gene's region involved (coding and non-coding) and mutations affecting the coding region in: single, multiple (at least with two bases involved) and deletion. We underline that for the listed mutations, reported in italic, literature doesn't provide all the biochemical or bio-molecular information or the research data. Finally, for the "old" mutations, we tried to verify features previously reported and, when subsequently modified, we updated the specific information using the latest literature data.

Prevalence and distribution of glucose-6-phosphate dehydrogenase (G6PD) variants in Thai and Burmese populations in malaria endemic areas of Thailand

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.

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in Pakistani population

INTRODUCTION

Glucose-6-phosphate dehydrogenase (G6PD; E.C. 1.1.1.49) deficiency is the commonest inborn error of metabolism with more than 140 genetic variants. The incidence of G6PD deficiency is 2-9% in Pakistan, but G6PD variants were never studied comprehensively. We therefore designed this study to describe the frequency of G6PD variants and their associated enzyme activities in Pakistan.

METHODS

Patients diagnosed with G6PD deficiency were enrolled. RFLP-PCR was utilized to identify common mutations previously reported from Asian countries. Where mutational analysis failed, amplification of 9-12 exons with subsequent gene sequencing was performed. G6PD enzyme activity was assessed through the quantitative enzyme assay.

RESULTS

Two hundred and seventy-six G6PD-deficient subjects (237 male and 39 women) were investigated. G6PD Mediterranean (563C-T) was the most common genetic variant (n=216 or 78%). G6PD Chatham (1003A-G) and G6PD Orissa (131C-G) were observed in 14 (5%) and two (0.7%) subjects respectively. A novel mutation 973 G-A with a predicated amino acid change of asp325asn was identified in exon 9. This was named G6PD Karachi after the place of origin of proband. Polymorphism in position 1311C/T was uniformly observed with all variants. Forty-three or 17% of DNA samples remained uncharacterized. Very low levels of G6PD enzyme activity was observed with 563C-T mutation.

CONCLUSION

We concluded that 563C-T was the commonest G6PD variant, while 1003A-G and 131C-G were less-frequent genetic variants of G6PD in Pakistani population. A novel genetic variant 973G-A was also identified. Very low levels of G6PD enzyme activity was seen with G6PD 563C-T. Mutational analysis failed in a significant proportion of samples warranting further work.