Molecular Data of Alpha Globin Gene Deletion in Thai: Twelve Years of Laboratory Service Experience at Siriraj Hospital

Abstract

          Alpha thalassemia ( thalassemia), a worldwide inherited disorder resulting in decreased or absent synthesis of alpha-globin chain of hemoglobin, mostly caused by gene deletions which can be detected by gap-PCR method. For twelve years of our laboratory service, during January 2002 to March 2014, we used a single tube multiplex gap-PCR technique to detect seven types of alpha globin gene deletion: Southeast Asia (--^SEA), Thai (--^THAI), Filipino (--^FIL), Mediteranean (--^MED), -()^20.5, -^4.2, -^3.7. The data from our survice has concordance with the previous studies, only four alleles, - -^SEA, - -^THAI,  -^3.7 and  -^4.2 were found with frequencies of 12.7, 0.3, 12.0 and 1.0 percents respectively while the remaining normal allele was found in 74 %.  In this study, the overall twelve types of -globin genotypes detected were  /, /--^SEA, /-^3.7, --^SEA/-^3.7, -^3.7 /-^3.7, /-^4.2, /--^THAI, --^SEA/-^4.2, -^3.7/-^4.2, --^THAI/^3.7, --^SEA/--^SEA and -^4.2/-^4.2   with frequencies of 55.03, 20.72, 15.40, 4.27, 1.99, 1.31, 0.49, 0.36, 0.24, 0.11, 0.06 and 0.02 percents respectively in 4,663 Thai samples. The study indicated that deletion of alpha thalassemia was heterogenous in Thai population. -thalassemia1 allele --^SEA that can cause Hb Bart’s hydrops fetalis, was found with the highest prevalence in our study.