Prenatal diagnosis of Hb Bart's hydrops fetalis by PCR technique: Pramongkutklao experience.

Hb Bart's hydrops fetalis is very common in Southeast Asia, especially in Thailand. As the mother of such an infant may suffer from toxemia of pregnancy, ante- or post-partum hemorrhage as well as the psychological burden for carrying a nonviable fetus to term, so prenatal diagnosis is indicated and the family should be given the choice of early termination of the pregnancy. Seven high risk pregnancies with Hb Bart's hydrops fetalis (homozygous alpha-thalassemia 1) were studied. Amniocentesis was done at 16-33 weeks of gestation. DNA analysis was performed by polymerase chain reaction (PCR) using 2 techniques, 1) three nucleotide primers and 2) four nucleotide primers. After either therapeutic abortion or birth, heart blood or cord blood was drawn to confirm the diagnosis by Hb electrophoresis and DNA analysis. Of 7 high risk fetuses, 3 were recognized as Hb Bart's hydrops fetalis, 2 showed the alpha-thal 1 trait, 1 showed alpha-thal 2 trait and 1 was a normal fetus. The technique was entirely suitable for prenatal diagnosis of Hb Bart's hydrops fetalis. This technique was a rapid, simple non-radioactive method, less expensive and available in most PCR laboratories.

Detection of DMD gene deletions in Thai children patients.

For the dystrophin gene, it has been shown that about 65% of DMD/BMD patients have detectable deletions. The majority of deletions are clustered in exons 45-53 and at the 5' terminus. We studied 14 X-linked muscular dystrophy (DMD) Thai child patients for detection of gene deletions by amplification of nine exons plus the promoter of the dystrophin gene in two multiplex polymerase chain reactions that included hot spot region (exons 45-53 and 5' terminus). There were 8 DMD patients who had incomplete gene deletion and most of the deletions were around exon 49. PCR-base assays will allow deletion detection from dry blood spot samples and prenatal diagnosis.