According to a study published recently in The American Journal of Human Genetics, a non-invasive, sequencing-based approach might offer a safer and more effective alternative to traditional methods for detecting chromosomal abnormalities in the developing fetus.
According to the study authors at Verinata Health, this method will provide mothers-to-be with a cost-effective way to find out whether their unborn baby will be born with major developmental problems by analysis of fetal DNA in the mother's blood, without risking a miscarriage.
This study is the first to show that almost all the information available about fetal DNA abnormalities obtained via an invasive procedure can also be available noninvasively.
Metaphase karyotypes, microscopic photos of chromosomes dividing, have traditionally been used to detect abnormalities that are associated with developmental delay, intellectual disability, birth defects, and autism in fetuses.
More recently, a method called a chromosome microarray, which uses molecular probes to detect gains or losses of pieces of DNA within chromosomes, has been shown to provide more accurate and detailed information than a metaphase karyotype.
The problem with both of these approaches is that they require invasive procedures that involve removing tissue from the placenta or inserting a needle into the amniotic sac to collect fluid. Both of them increase the risk of infection and could even harm the fetus during pregnancy.
It’s been known that a noninvasive method called massively parallel sequencing (MPS) of fetal DNA offers a safer alternative for spotting chromosomal abnormalities in the fetal genome. But so far it has been unclear whether MPS is as accurate as chromosome microarrays.
In this new study, the Verinata Health team found that MPS was indeed capable of detecting a wide variety of chromosomal abnormalities just as accurately as chromosome microarrays.
Such a safe, effective and noninvasive test has major clinical implications, particularly for women who either have a medical contraindication or don’t have access to an invasive procedure.
This finding suggests that noninvasive detection of abnormalities in the fetal genome might be commonplace in the very near future, providing much-needed relief to anxious prospective parents and their physicians.