Background: To evaluate thalassemia carrier screening program using red blood count indices (RBC) at Hung Vuong hospital, Ho Chi Minh City, Viet Nam, from June 2010 to March 2013.
Methods: All pregnant women visiting Hung Vuong hospital were screened thalassemia carrier by using RBC. Serum ferritin and hemoglobin electrophoresis were performed among microcytic hypochromic anemia women [mean cellular volume (MCV) <80 fL or mean cellular hemoglobin (MCH) <28 pg]. Their partners were also asked to be screened by these tests. The anemia couples were consulted to identify thalassemia mutation. The couples who were at high risk of having thalassemia major fetus were then advised to undergo invasive procedure such as amniocentesis or cordocentesis. The couples having confirmed thalassemia major fetus were offered pregnancy termination.
Results: Among 2,982 microcytic hypochromic anemia pregnant women, 21% of them (633/2,982) have their partners detected to have the same condition. Among those anemia couples, 51% (324/633) were both alpha thalassemia carriers, 10% (62/633) were both beta thalassemia carriers and 39% (247/633) were two different types of thalassemia carriers. Among alpha thalassemia mutations, --SEA mutation has the highest proportion (67%, 337/502). The mean of MCV and MCH of --SEA mutation carriers were 67.9±4.7 and 21.9±1.5 respectively. Among 1,249 beta thalassemia cases diagnosed through RBC and hemoglobin electrophoresis, 54% (678/1,249) had HbE peak with 75.7±5.1 MCV and 25.2±1.9 MCH and the other 46% (571/1,249) had 67.7±6.7 MCV and 22±2.3 MCH. Among the couples who were both microcytic hypochromic anemia, only 33% (209/633) of them agreed to undergo amniocentesis or cordocentesis to identify the affected fetuses. We found 40 hemoglobin Bart hydrops fetalis syndrome cases and 4β thalassemia major cases. All the thalassemia major fetuses were terminated, except 1β thalassemia major fetus carrying Cd 26 (HbE disease) and Cd 41/42 mutations.
Conclusions: Thalassemia is a common inherited condition in Viet Nam. The number of α thalassemia carriers is twice as many as beta thalassemia carriers. --SEA and CD 26 (HbE disease) mutations are the most common mutations of α thalassemia and beta thalassemia, respectively. In order to reduce the number of major thalassemia fetuses, thalassemia screening strategy by RBC in preconceptional couples or in first-visit pregnant women is effective and applicable in Viet Nam.
