The Level of Hemoglobin A2 of Double Heterozygous α-Thalassemla / β-Thalassemia

Abstract

Hydrops Fetalis Syndrome is a serious disorder, usually indicative of a poor prognosis of the affected fetus. In Southeast Asia, α-thalassemia is the most common cause of fetal hydrops. The fetus or the infant died within an hour after birth. It was estimated that half of the mothers could die from complications resulting from these pregnancies in case of no medical care. For prevention of Hydrops Fetalis, The National Thalas-semia Policy should provide with genetic diagnostic of α° thalassemia to identify couples at risk (Carrier Detection) and provide them with timely counseling and prenatal diagnosis during early pregnancy. The major problem of α° thalassemia carrier identification was its underdiagnosis among β thalassemia carrier with α° thalassemia carrier cases. The objective of this research was to study the level of Hemoglobin A₂ in double heterozygous α-thalassemial/β-thalassemia (β-thalassemia trait with α° thalassemia trait) group compared with β-thalassemia trait group. α° thalassemia PCR, MCV, MCH and Hb value were used to creat the criteria to identify α° thalassemia couple risk from β-thaIassemia case.

ln this study, 50 cases of β-thalassemia trait had the level of HbA₂ = 4.1%-6.6%. 2 of 50 cases (4%) were double heterozygous α-thalassemia/ β-thalassemia (β thalassemia trait with α° thalassemia trait) had the level of HbA₂ = 5.6% and 6.1%. The value of Hb, MCV, MCH, RDW were also not significantly different from the other B-thalassemia trait cases. Thus, for prevent Hydrops Fetalis, The National Thalassemia Policy should provided genetic diagnostic of α° thalassemia to β thalassemia carrier cases.