Prenatal Diagnosis of Thalassemia and Hemoglobinopathies: 20 Years Experience at Siriraj Hospital

Abstract

Objective: To show the experience of prenatal diagnosis of Thalassemia and hemoglobinopathies in Siriraj Hospital. Methods: Hb Bartûs hydrops fetalis can be detected by DNA study from polymerase chain reaction (PCR) product in the first trimester of pregnancy either by chorionic villus sampling (CVS) or aminocentesis but in late pregnancy it can be detected unambiguous by ultrasonography at 18-20 weeks gestation, the suspected cases are confirmed by fetal blood sampling and Hb electrophoresis. Prenatal diagnosis (PND) for β-thalassemia diseases can be done at early pregnancy by direct visualization of the PCR products on electrophoresis or by dot blot analysis of amplified DNA with a set of HRP-labeled oligonucleotide probes complementary to the mutations. If the mutation is unknown. The couples have to wait for Hb analysis by HPLC or in vitro globins chain analysis from fetal blood in the second trimester. Results: The results of PND at Siriraj Hospital are summarized as Hb Bartûs Hydrops fetalis 228 cases, Homozygous BetaThalassemia 126 cases, and Beta Thalassemia/Hb E disease 550 cases. There are various methods of sampling namely chorionic villous sampling, amniocentesis, fetal blood sampling, ultrasound, or even combined method. There are minimal incidences of fetal loss 9 out 904 cases which, comparatively give us one of the best center for prenatal diagnosis in Asia. Conclusion: Of the 904 pregnancies, the diagnosis were obtained in 891 pregnancies in which had 5 fetal loss from dead fetus in utero after fetal blood sampling in the second trimester. The other complication occurred after sampling failure.

Keywords

• Amniocentesis
• chorionic villus sampling (CVS)
• fetal blood sampling (FBS)
• HPLC
• PCR
• prenatal diagnosis (PND)