A Minimal Set of SNPs for the Noninvasive Prenatal Diagnosis of β‐Thalassaemia

Abstract

Summaryβ-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.

Non invasive prenatal diagnosis of ?- Thalassemia, A narrative review study

“…The results of this study revealed that, 72.28% of couples eligible for qualitative SNPs based NIDP, 92% are quantitative detection. They believe that this method is sensitive and specific for detection of paternally inherited mutation in maternal plasma 40 .…”

Next generation sequencing of SNPs for non-invasive prenatal diagnosis: challenges and feasibility as illustrated by an application to β-thalassaemia

“…SNPs rs968857_3 0 cb and rs7480526_II74 were selected after a genotyping analysis carried out in a previous study, 26 whereas SNPs rs10768683_AvaII and rs3834466_IIe are routinely used in Cyprus for prenatal diagnosis. 27 Two of the SNPs are located within the b-globin gene and the other two SNPs 5 0 to the d-globin gene, therefore, any recombination events would be instantly recognisable.…”

“…26 SNPs were considered informative when the mother was homozygous and the father was heterozygous for the same SNP. Ten families having at least two informative SNPs of the four analysed above were selected for the NGS analysis.…”

Non‐invasive prenatal testing for fetal inheritance of maternal β‐thalassaemia mutations using targeted sequencing and relative mutation dosage: a feasibility study

“…Invasive prenatal diagnosis (IPD) for pregnancies at risk of a haemoglobinopathy can be offered, but due to a procedure‐related risk of miscarriage of 0.1–0.2%, non‐invasive prenatal diagnosis (NIPD) without risk of pregnancy loss is preferable. Following the discovery of cell‐free fetal DNA (cffDNA) in maternal plasma, many studies have been conducted using this source of genetic material to develop NIPD for β ‐thalassaemia . Most focus on detecting inheritance of paternal mutations when parents carry different mutations .…”