Arrayed primer extension for the noninvasive prenatal diagnosis of beta-thalassemia based on detection of single nucleotide polymorphisms.

beta-Thalassemia is one of the most common autosomal recessive single-gene disorders in Cyprus. Development of a noninvasive prenatal diagnostic (NIPD) assay for beta-thalassemia is based mostly on the detection of paternally inherited single nucleotide polymorphisms (SNPs) using the arrayed primer extension (APEX) method. Eleven SNPs with high degree of heterozygosity in the Cypriot population were selected and analyzed on 34 families and the informative SNPs were determined. The APEX assay was used on maternal plasma of seven families using the informative SNPs; paternal allele of the fetus was noninvasively detected in five families.