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

• Main Authors: Thanusak Tatu, Waratip Sritong, Torpong Sa-Nguansermsri
• Format: Journal
• Published: 2018
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84902284949&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/45307
• Institution: Chiang Mai University

At least three genetic factors including β-thalassemia mutations, α-thalassemia, and XmnI- G γ 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- G γ 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- G γ 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 β O and β + ) were found. Twenty-nine point one percent of the patients had at least one XmnI- G γ site (XmnI- G γ: +) 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- G γ 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- G γ polymorphism and the SEA-α thalassemia 1, in management and prenatal diagnosis of β-thalassemia in northern Thailand.