Blood test can find thousands of genetic conditions in pregnancy, say scientists
A new non-invasive maternal blood test can detect up to 99% of genetic variants in a foetus, potentially reducing the need for invasive procedures like amniocentesis.
Scientists have developed a new maternal blood test that can detect thousands of serious genetic conditions in a developing foetus, potentially limiting the need for invasive screening during pregnancy. The technique, called non-invasive foetal sequencing (NIFS), will be presented at the European Society for Human Genetics conference in Gothenburg.
The test works by detecting tiny fragments of foetal DNA circulating in the mother's bloodstream. Using advanced sequencing, researchers identified a high proportion of genetic conditions such as cystic fibrosis, which currently require amniocentesis or other invasive tests for reliable diagnosis.
Dr Christopher Whelan, a senior computational scientist at the Broad Institute of MIT and Harvard, said the test can detect thousands of serious conditions, including most of those on major newborn sequencing panels, such as the over 2,500-gene Genomics England foetal anomalies panel. Examples include Noonan syndrome, Charge syndrome, Stickler syndrome, and achondroplasia.
The researchers tested NIFS on 565 pregnancies at an average of 17 weeks gestation. By sequencing DNA fragments and using computational methods, they identified genetic variants across nearly 23,000 genes per foetus. Comparing results with amniocentesis or chorionic villus sampling (CVS), the test detected 95-99% of genetic variants and over 97% of clinically relevant variants.
Prof Alexandre Reymond of the University of Lausanne called it a "tour de force" that will change reproductive medicine. However, Prof Angus Clarke, a clinical geneticist at Cardiff University, warned that exploratory screening could reveal genes of unknown significance, causing parental anxiety and unnecessary medicalisation.
