Analysis of real-time PCR cycle threshold of alpha-thalassemia-1 Southeast Asian type deletion using fetal cell-free DNA in maternal plasma for noninvasive prenatal diagnosis of Bart's hydrops fetalis
Pornprasert, S.; Sukunthamala, K.; Kunyanone, N.; Sittiprasert, S.; Thungkham, K.; Junorse, S.; Pongsawatkul, K.; Pattanaporn, W.; Jitwong, C.; Sanguansermsri, T.
Journal of the Medical Association of Thailand 93(11): 1243-1248
2010
ISSN/ISBN: 0125-2208 PMID: 21114201 Document Number: 10940
Noninvasive prenatal diagnosis based on detection of fetal cell-free DNA is hampered when mother and father are both carriers for the same autosomal recessive mutation. To compare the diagnosis of Bart's hydrops fetalis using conventional Gap-PCR analysis of fetal cells/tissues with the measurement of quantitative difference (deltaCp) between alpha-thalassemia-1 SEA type deletion gene (C(T-mutant)) and wild type alpha-globin gene (C(T-wild type)) in plasma of pregnancies by using the Taqman real-time quantitative PCR. Plasma DNA samples were collected from three groups of pregnancies whose fetuses have known thalasemia status (7 normal, 11 heterozygote alpha-thalassemia-1 SEA type deletion, and 7 Bart's hydrops fetalis). The alpha-thalassemia-1 SEA type deletion gene and wild type alpha-globin gene were quantified by using Taqman real-time quantitative PCR and then the delta C(T) was analyzed by subtracting the C(T-mutant) from C(T-wild type). Mean deltaC(T) values were not significantly different among the three groups. However, women whose fetuses were diagnosed as Bart's hydrops fetalis had a higher proportion (43%) of plasma DNA samples that had negative deltaC(T) value than women whose fetuses were diagnosed as normal or heterozygote alpha-thalassemia-1 SEA type deletion (0 and 27%, respectively). Further investigations are needed to improve the diagnosis of Bart's hydrops fetalis using fetal cell-free DNA.
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