Molecular Epidemiology of Hemoglobinopathies in Cambodia

Abstract

Determining the magnitude of the thalassemia problem in a country is important for implementing a national prevention and control program. In order to acquire accurate thalassemia prevalence data, the gene frequency of α- and β-thalassemia (α- and β-thal) in different regions of a country should be determined. The molecular basis of thalassemia in Cambodia was performed by polymerase chain reaction (PCR)-based techniques in a community-based cross-sectional survey of 1631 unrelated individuals from three regions, Battambang, Preah Vihear and Phnom Penh. Thalassemia mutations were detected in 62.7% of the three studied population of Cambodia. Hb E (HBB: c.79G > A) was the most common β-globin gene mutation with a frequency ranging from 0.139 to 0.331, while the most frequent α-globin gene mutation was the –α^3.7 (rightward) deletion (0.098–0.255). The other frequencies were 0.001–0.003 for β-thal, 0.008–0.011 for α-thal-1 (– –^SEA), 0.003-0.008 for α-thal-2 [–α^4.2 (leftward deletion)], 0.021–0.044 for Hb Constant Spring (Hb CS, HBA2: c.427T > C) and 0.009–0.036 for Hb Paksé (HBA2: c.429A > T). A regional specific thalassemia gene frequency was observed. Preah Vihear had the highest prevalence of Hb E (55.9%), α-thal-2 (24.0%) and nondeletional α-thal (15.1%), whereas Phnom Penh had the lowest frequency of thalassemia genes. Interestingly, in Preah Vihear, the frequency of Hb Paksé was extremely high (0.036), almost equivalent to that of Hb CS (0.044). Our results indicate the importance of micromapping and epidemiology studies of thalassemia, which will assist in establishing the national prevention and control program in Cambodia.

• α-Thalassemia (α-thal)
• β-thalassemia (β-thal)
• Cambodia
• Hb Constant Spring (Hb CS)
• Hb E
• Hb Paksé

Acknowledegments

We thank the Director of the National Institute of Public Health (NIPH), Phnom Penh for his support and the NIPH laboratory staff for their assistance with the collection, processing and storage of specimens. TM, JT contributed to the performance of the experiments, analyzed the data and drafted the manuscript. PB, PW and SF contributed to the concept of the study and analysis of data. BM, MY, JG contributed to the concept of the study and specimen collection. RD contributed to the concept of the study and CBC analysis. SS was responsible for the study design, concept of the study, analysis of data and drafting the manuscript. Final approval of the version to be published was made by all authors.

Declaration of interest

The conceptualization, data collection and preliminary analysis was funded by World Vision Canada and executed by World Vision Cambodia. This study was supported by Mahidol University Research Grants, Office of the Higher Education Commission and Mahidol University under the National Research University Initiative, the Research Chair Grant, the National Science and Technology Development Agency (NSTDA) and Thailand Research Fund (IRG5780009). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.