November 9, 2017

expert reaction to study looking at new DNA antenatal screening for Down’s syndrome

A new study, published in Genetics in Medicine, looks at incorporating DNA analysis into antenatal screening for three chromosome disorders, including Down’s syndrome.

Prof. Darren Griffin, Professor of Genetics, University of Kent, said:

“Non-invasive prenatal testing is now becoming quite commonplace and is rapidly replacing metabolite screening and invasive prenatal diagnosis such as amniocentesis.

“This study is a collation of about 2 years’ work in which the authors first performed metabolite screening to establish a high risk group, hung on to the sample and then performed DNA sequencing of the foetal fraction in maternal blood to screen for the chromosome abnormalities that are compatible with live birth.  Of the 22,000 samples originally screened, around 2500 were assessed for chromosome abnormalities.

“Perhaps the biggest selling point of the paper is that by combining the approaches and selecting a smaller group for screening (the ‘reflex’ approach) by choosing only a small subset for sequencing on the same sample, the approach is one that is cost efficient – only requiring one blood draw.

“Several labs are performing non-invasive prenatal testing (NIPT) and the false positive rate here is equivalent to what many of the others are reporting.”

* ‘Prenatal reflex DNA screening for trisomies 21, 18, and 13’ by Nicholas J. Wald et al. published in Genetics in Medicine on Thursday 9 November 2017.

Declared interests

Prof. Darren Griffin: “One of the authors (Robert Old) is my brother in law.  We have funding from another (unrelated) company – Genesis Genetics – that also perform NIPT.”