Prevalence of thalassemia trait from screening program in pregnant women of Phitsanulok

Abstract

Abstract: Thalassemia is the leading genetic problem in Thai population. Prevalence of thalassemia trait in Thais differs from different regions making different proportions of spouses at risk and thalassemic disease births. With the preliminary data from thalassemia screening in 550 pregnant women which conducted at Buddhachinaraj hospital, Phitsanulok province, during August to
December 2002. There were 1.63% beta thalassemia trait, 21.27% hemoglobin E trait, 2.18% homozygous Hb E (using DEAE sephadex microcolumn chromatography and high performance liquid chromatography) and 7.09% alpha thalassemia-1 trait (using polymerase chain reaction technique for Southeast asian-type alpha thalassemia-1). From these genotypic frequencies, we can estimate the allelic frequencies and calculate for major thalassemic diseases using Hardy-Weinberg formulation. In 2001, there were 8,877 pregnant women attended for antenatal care at all hospitals in Phitsanulok. Thus, we can estimate the fetuses with major thalassemic disease should be homozygous beta thalassemia 0-1 case, compound heterozygous for beta thalassemia and Hb E 18
cases and homozygous alpha thalassemia-1 11 cases per year in Phitsanulok. In practical way, screening thalassemia in pregnant women, perform prenatal diagnosis in spouses at risk and consider therapeutic abortion in major thalassemic fetuses seems to be the only cost-effective method for controlling major thalassemias. Therefore, researches aiming at thalassemic prevention should be worth growing and help solving thalassemic problem in Thais.