Summary
β‐thalassaemia is one of the commonest autosomal recessive single‐gene disorders worldwide. Prenatal tests use invasive methods, posing a risk for the pregnancy itself. Development of a ...noninvasive prenatal diagnostic method is, therefore, of paramount importance. The aim of the present study is to identify high‐heterozygote informative single‐nucleotide polymorphisms (SNPs), suitable for the development of noninvasive prenatal diagnosis (NIPD) of β‐thalassaemia. SNP genotyping analysis was performed on 75 random samples from the Cypriot population for 140 SNPs across the β‐globin cluster. Shortlisted, highly heterozygous SNPs were then examined in 101 carrier families for their applicability in the noninvasive detection of paternally inherited alleles. Forty‐nine SNPs displayed more than 6% heterozygosity and were selected for NIPD analysis, revealing 72.28% of the carrier families eligible for qualitative SNP‐based NIPD, and 92% for quantitative detection. Moreover, inference of haplotypes showed predominant haplotypes and many subhaplotypes with sufficient prevalence for diagnostic exploitation. SNP‐based analyses are sensitive and specific for the detection of the paternally inherited allele in maternal plasma. This study provides proof of concept for this approach, highlighting its superiority to NIPD based on single markers and thus providing a blueprint for the general development of noninvasive prenatal diagnostic assays for β‐thalassaemia.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Summary beta-thalassaemia is one of the commonest autosomal recessive single-gene disorders worldwide. Prenatal tests use invasive methods, posing a risk for the pregnancy itself. Development of a ...noninvasive prenatal diagnostic method is, therefore, of paramount importance. The aim of the present study is to identify high-heterozygote informative single-nucleotide polymorphisms (SNPs), suitable for the development of noninvasive prenatal diagnosis (NIPD) of beta-thalassaemia. SNP genotyping analysis was performed on 75 random samples from the Cypriot population for 140 SNPs across the beta-globin cluster. Shortlisted, highly heterozygous SNPs were then examined in 101 carrier families for their applicability in the noninvasive detection of paternally inherited alleles. Forty-nine SNPs displayed more than 6% heterozygosity and were selected for NIPD analysis, revealing 72.28% of the carrier families eligible for qualitative SNP-based NIPD, and 92% for quantitative detection. Moreover, inference of haplotypes showed predominant haplotypes and many subhaplotypes with sufficient prevalence for diagnostic exploitation. SNP-based analyses are sensitive and specific for the detection of the paternally inherited allele in maternal plasma. This study provides proof of concept for this approach, highlighting its superiority to NIPD based on single markers and thus providing a blueprint for the general development of noninvasive prenatal diagnostic assays for beta-thalassaemia. PUBLICATION ABSTRACT
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
β-Thalassaemia is one of the most common autosomal recessive single-gene disorder worldwide, with a carrier frequency of 12% in Cyprus. Prenatal tests for at risk pregnancies use invasive methods and ...development of a non-invasive prenatal diagnostic (NIPD) method is of paramount importance to prevent unnecessary risks inherent to invasive methods. Here, we describe such a method by assessing a modified version of next generation sequencing (NGS) using the Illumina platform, called 'targeted sequencing', based on the detection of paternally inherited fetal alleles in maternal plasma. We selected four single-nucleotide polymorphisms (SNPs) located in the β-globin locus with a high degree of heterozygosity in the Cypriot population. Spiked genomic samples were used to determine the specificity of the platform. We could detect the minor alleles in the expected ratio, showing the specificity of the platform. We then developed a multiplexed format for the selected SNPs and analysed ten maternal plasma samples from pregnancies at risk. The presence or absence of the paternal mutant allele was correctly determined in 27 out of 34 samples analysed. With haplotype analysis, NIPD was possible on eight out of ten families. This is the first study carried out for the NIPD of β-thalassaemia using targeted NGS and haplotype analysis. Preliminary results show that NGS is effective in detecting paternally inherited alleles in the maternal plasma.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
beta-Thalassaemia is one of the most common autosomal recessive single-gene disorder worldwide, with a carrier frequency of 12% in Cyprus. Prenatal tests for at risk pregnancies use invasive methods ...and development of a non-invasive prenatal diagnostic (NIPD) method is of paramount importance to prevent unnecessary risks inherent to invasive methods. Here, we describe such a method by assessing a modified version of next generation sequencing (NGS) using the Illumina platform, called 'targeted sequencing', based on the detection of paternally inherited fetal alleles in maternal plasma. We selected four single-nucleotide polymorphisms (SNPs) located in the beta-globin locus with a high degree of heterozygosity in the Cypriot population. Spiked genomic samples were used to determine the specificity of the platform. We could detect the minor alleles in the expected ratio, showing the specificity of the platform. We then developed a multiplexed format for the selected SNPs and analysed ten maternal plasma samples from pregnancies at risk. The presence or absence of the paternal mutant allele was correctly determined in 27 out of 34 samples analysed. With haplotype analysis, NIPD was possible on eight out of ten families. This is the first study carried out for the NIPD of beta-thalassaemia using targeted NGS and haplotype analysis. Preliminary results show that NGS is effective in detecting paternally inherited alleles in the maternal plasma.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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