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Prenatal diagnosis of homozygous alpha‐thalassemia‐1 by cell‐free fetal DNA in maternal plasma
Author(s) -
Sirichotiyakul S.,
Charoenkwan P.,
Sanguansermsri T.
Publication year - 2012
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.2892
Subject(s) - cell free fetal dna , prenatal diagnosis , thalassemia , alpha thalassemia , obstetrics , fetus , beta thalassemia , medicine , alpha (finance) , hemoglobinopathy , pregnancy , genetics , biology , immunology , genotype , hemolytic anemia , surgery , gene , construct validity , patient satisfaction
Objective To investigate the use of cell‐free fetal DNA (cff‐DNA) to determine fetal status in pregnant women who were risk for having Hb Bart's. Methods Plasma DNA was extracted from 10 mL of maternal blood from couples who both were alpha‐thalassemia‐1 carriers (SEA deletion). Real time quantitative PCR was performed using fluorescence‐labeled probes to monitor wild type (wt) and SEA allele. The quantity of each allele was determined by cycle threshold ( Ct ). Δ Ct ( Ct of wt– Ct of SEA) was calculated from each sample. Prenatal diagnosis was performed to determine fetal status. Result There were 62 Hb Bart's, 62 alpha‐trait and 34 normal fetuses in this study. Mean Δ Ct was 1.04 ± 0.38, 0.21 ± 0.37 and 0.14 ± 0.55 in Hb Bart's, alpha‐trait and normal fetuses, respectively. Based on ROC, the best cut‐off of Δ Ct for predicting Hb Bart's was 0.51, giving 98.4% sensitivity and 20.8% false‐positive rate. All but one Hb Bart's (98.4%) had Δ Ct above 0.51, whereas 74.2% of alpha‐trait and 88.2% of normal fetuses had Δ Ct below 0.51. Conclusion There is a positive trend to use cff‐DNA in maternal plasma for prenatal diagnosis of homozygous alpha‐thalassemia‐1. With this technique, invasive prenatal testing and complications can be avoided in 79.2% of unaffected fetuses. © 2011 John Wiley & Sons, Ltd.