The Associations of SEA-α Thalassemia 1, XmnI-Gγ
Polymorphism and β-Globin Gene Mutations with
the Clinical Severity of β-thalassemia Syndrome
in Northern Thailand
Thanusak Tatu PhD*,***,
Waratip Sritong MS*, Torpong Sa-nguansermsri MD**
Affiliation :
* Division of Clinical Microscopy, Department of Medical Technology, Faculty of Associated Medical Sciences,
Chiang Mai University, Chiang Mai, Thailand
** Thalassemia Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
*** Biomedical Technology Research Center, Faculty of Associated Medical Sciences,
Chiang Mai University, Chiang Mai, Thailand
Background : At least three genetic factors including β-thalassemia mutations, α-thalassemia, and XmnI-Gγ polymorphism
were shown to modify clinical symptoms in β-thalassemia disease.
Objective : To determine associations of β-thalassemia mutations, SEA-α thalassemia 1, and XmnI-Gγ polymorphism, and
clinical severity of β-thalassemia in northern Thailand.
Material and Method: Thirty-two β-thalassemia major and 28 β-thalassemia intermedia attending the Thalassemia Clinic
at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand were recruited. The β-globin gene mutations and SEA-α
thalassemia 1 were determined by MS-PCR and Gap-PCR, respectively. The XmnI-Gγ polymorphism was identified by RFLP
analysis. Odds ratio was calculated to evaluate the associations of these three genetic factors and clinical symptoms.
Results : Eight β-globin gene mutations (both βO and β+) were found. Twenty-nine point one percent of the patients had at
least one XmnI-Gγ site (XmnI-Gγ: +) and 4.1% of the patients were heterozygote for the SEA-α thalassemia 1. The β-globin
gene mutations showed maximal impact and the XmnI-Gγ polymorphism had minimal influence on clinical severity in this
cohort. The SEA-α thalassemia 1 had the least effect on the clinical severity due to its low prevalence in these patients.
Conclusion : Although these three genetic factors play roles in modifying clinical symptoms of β-thalassemia, the β-thalassemia
mutations should be considered first, followed respectively by the XmnI-Gγ polymorphism and the SEA-α thalassemia 1, in
management and prenatal diagnosis of β-thalassemia in northern Thailand.
Keywords : β-thalassemia, HbE/β-thalassemia, β-thalassemia mutations, SEA-α thalassemia 1, XmnI-Gγ polymorphism, HbE
All Articles
Download