The current trusted method of testing for chromosomal anomalies in the fetus involves an invasive procedure where amniotic fluid is drawn from the amniotic sac and tested. The procedure is expensive and posts risk of infection and fetal harm. Researchers recently published a report in the American Journal of Human Genetics, claiming a non-invasive procedure is available that provides the same information without the invasive procedure.
The new procedure involves a maternal blood draw and subsequent non-invasive test of the blood sample. According to researchers, the results of the blood test are nearly identical to that of the invasive test. The old test used microscopic images taken of amniotic fluid to detect chromosomal anomalies. Advances in medical technology recently added chromosome microarray to the test to improve the results.
The maternal blood test uses MPS (massively parallel sequencing) to achieve nearly the same results. The non-invasive test was able to detect duplications, microdeletions and translocations. Trisomy 20 was also blindly detected. Researchers noted that 300kb microdeletions were detectable with the non-invasive procedure.
While the test will not be widely used for quite some time, researchers hope the study results will open the medical community to the possibility that a new, non-invasive test could eventually all but replace the invasive amniotic test currently in use.
It is important to note that even though current testing is invasive, risk of negative side effects or harm to the fetus are extremely low.
Anupama Srinivasan, Diana W. Bianchi, Hui Huang, Amy J. Sehnert, Richard P. Rava. Noninvasive Detection of Fetal Subchromosome Abnormalities via Deep Sequencing of Maternal Plasma. The American Journal of Human Genetics, 2013; DOI: 10.1016/j.ajhg.2012.12.006