Take DiGeorge syndrome for example. In Taiwan, 1 out of every 4000 babies are born with this condition and require professional medical care from the moment of birth. This syndrome mostly results from tiny defects in chromosome 22, of which 10% result from autosomal dominant inheritance and 90% result from spontaneous mutations.

Using the Whole Genome Sequencing (WGS) technique facilitated by NIPS, we are able to retrieve the complete fetal DNA profile from the mother's blood. We can then determine the number of chromosomes and chromosome segments by calculating the copy number variation (CNV) of fetal DNA. This practice is relatively easy and is less dangerous than amniotic fluid sampling.

If an ultrasound determines that the fetus has an abnormally formed heart (a common sign of chromosomal disorders), a fetal chromosome sample can be retrieved at 14-weeks of pregnancy. To ensure the integrity of the fetal chromosome and to perform genetic testing in the safest way possible, NIPS is the best and only choice.

According to the lab report, there was a small deletion on chromosome 22. The fetus was confirmed to have DiGeorge syndrome, which would likely result in heart defects, dyscrinism, growth retardation, and mental retardation. If the condition was severe, the life span of the baby may not have exceeded one month. As a result, the testee decided to terminate the pregnancy prior to the legal 24-week time-limit.

At this stage, NIPS targets 20 types of chromosome deletion syndromes which are common in Taiwan. The accuracy and sensitivity of this screening technique can reach 99.5%.