Accurate prenatal diagnosis of Hb Bart's hydrops fetalis in daily practice with a double-check PCR system.
Hemoglobin (Hb) Bart's hydrops fetalis is a fatal condition associated with homozygous alpha(0)-thalassemia. Prenatal diagnosis of the disease is usually done by gap-PCR; however, misdiagnosis can occur with allelic dropout. Diagnosis using more than one method is preferred. We describe a double-check PCR assay for accurate prenatal diagnosis. The study was conducted on 64 fetuses at risk of homozygous alpha(0)-thalassemia encountered at our routine thalassemia diagnosis laboratory. Chorionic villus sample (CVS), amniotic fluid or fetal blood specimens were obtained from pregnant women at risk and analyzed by two PCR methods. In the first method, the SEA alpha(0)-thalassemia deletion of parents and fetuses were determined by gap-PCR routinely run in our laboratory. In another method, two specific fragments located 5' to the zeta(2) gene (XbaI fragment) and the alpha(2)-globin gene (RsaI fragment) together with the gap-PCR fragment were multiply co-amplified to determine the presence or absence of normal and alpha(0)-thalassemia alleles. The molecular diagnosis of alpha(0)-thalassemia was possible in all 64 fetuses using the two PCR approaches. The final diagnoses included 13 normal, 29 unaffected heterozygote and 22 homozygote alpha(0)-thalassemia fetuses.The two PCR assays disclosed no discordant result in the diagnosis of the Hb Bart's hydrops fetalis caused by alpha(0)-thalassemia.The combined PCR assay for gap-PCR, zeta(2) XbaI and alpha(2) RsaI fragments, described here, is simple, accurate and applicable in the prenatal diagnosis of Hb Bart's hydrops fetalis in a routine setting.
Karnpean
Rossarin
R
Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.
Fucharoen
Goonnapa
G
Fucharoen
Supan
S
Sae-ung
Nattaya
N
Sanchaisuriya
Kanokwan
K
Ratanasiri
Thawalwong
T
D000649:Amniocentesis; D015193:Chorionic Villi Sampling; D017218:Cordocentesis; D004252:DNA Mutational Analysis; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005838:Genotype; D006455:Hemoglobins, Abnormal / Q000032:analysis / Q000235:genetics*; D006801:Humans; D015160:Hydrops Fetalis / Q000175:diagnosis* / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000235:genetics; D011272:Pregnancy, Multiple; D011296:Prenatal Diagnosis / Q000379:methods*; D012680:Sensitivity and Specificity; D017384:Sequence Deletion; D013789:Thalassemia / Q000175:diagnosis / Q000235:genetics; D055542:alpha-Globins / Q000235:genetics; D017085:alpha-Thalassemia / Q000175:diagnosis / Q000196:embryology / Q000235:genetics
D006455:Hemoglobins, Abnormal; D055542:alpha-Globins; C030448:hemoglobin Bart's; C035541:Hemoglobin Constant Spring