We had the pleasure of interviewing Miguel Milan, Molecular Biologist specialized in Genetics and coordinator of the Test Born, a non-invasive prenatal test from the Igenomix laboratory that detects chromosomal abnormalities and is presented as a safe alternative to amniocentesis.
Amniocentesis is a prenatal test, which, being invasive, worries pregnant women a lot. Today there are alternatives such as the NACE Test, which is done only with a blood sample from the mother. We wanted to know first hand what the test is about, what it detects, how it is performed and other questions that will interest you to future moms and that the expert has answered us very kindly.
What is NACE and how does it work?
The NACE is a prenatal screening technique with which you can analyze, quickly and safely, the presence or absence of the most prevalent chromosomal alterations in evolutionary pregnancies. Unlike other techniques, such as amniocentesis, NACE is a non-invasive technique, and a sample of maternal blood is simply required, such as that used for any routine analysis.
The basis of the NACE test is very simple. We all have circulating and free DNA in our bloodstream. In the case of pregnant women, in your bloodstream you can find, in addition to your own, free DNA from the placenta of the baby you are pregnant with. Once we receive the blood sample, we extract the circulating DNA from both and count the amount of DNA for the chromosomes that are analyzed in the test using molecular techniques.
In the case of the NACE test, whose procedure is performed in our laboratories in Spain, parents can have the chromosome result of their future baby in just 3 working days from the moment we receive the blood in the laboratory. In the case of Expanded NACE, because part of the procedure is carried out outside Spain, the waiting time is a little longer, between 7 and 10 working days since we received the blood sample.
What anomalies does it detect? With what reliability?
"With the NACE test, parents can have the chromosome result of their future baby in just 3 working days"
He NACE test analyzes the fetal chromosomal status of chromosomes 13, 18, 21, and of the sex chromosomes X and Y. In the case of NACE test Expanded, additionally detects alterations for chromosomes 9 and 16, and alterations for the 6 most prevalent microdeletions: DiGeorge syndrome, 1p36 deletion syndrome, Angelman syndrome, Prader Willy syndrome, Cri du Chat syndrome and Wolf syndrome -Hirschhorn.
In terms of reliability, the NACE test is the most robust in the market. We offer results in practically all of the samples we receive, with a very high sensitivity and specificity for the chromosomes analyzed in the test. For example, anomalies for chromosome 21 are detected 99.8% of the time.
What is the best time of pregnancy to perform the test? How is it done?
As pregnancy progresses, the amount of fetal DNA in the maternal blood increases. The NACE test can be performed successfully from the 10th week of pregnancy, although it would be advisable to perform the test once the 12-week ultrasound check has been performed.
The procedure to perform the NACE test is very simple. From the 10th week of pregnancy, only a conventional blood draw is necessary, of those obtained in any routine blood test. Fast and easy.
Can you detect risk of spontaneous abortion in the first weeks of pregnancy?
No, this test is designed to detect those chromosomal abnormalities that are compatible with an evolutionary pregnancy. In addition, the majority of spontaneous abortions occur before the 10-12 week of pregnancy (which is when we can collect the blood to analyze it) so, although the test could detect chromosomal abnormalities that produce early miscarriage, the test would not be clinically useful
Do you think tests like NACE will mean the end of amniocentesis?
The NACE test can be performed successfully from the 10th week of pregnancy, but it would be advisable once the 12-week ultrasound was performed.
The NACE test is a powerful screening test, which will allow very accurately detect pregnancies with a chromosomally normal fetus. Before the existence of the test, many of these patients, by age or other indications, would have undergone an invasive procedure, including amniocentesis. If we talk about numbers, we can be talking about the fact that approximately 90% of the patients to whom an amniocentesis would be recommended because they are risk patients would not need to be performed since the NACE test is being offered.
Thus, In the short term, a reduction in the number of amniocentesis to be performed is expected, and the indication of amniocentesis will be restricted to a limited number of cases.
The NACE test, like the rest of prenatal screening techniques based on free fetal DNA circulating in maternal blood, is based on the analysis of placental cell DNA. It is therefore an indirect technique. Although in a very low percentage, there are cases in which the chromosomal state of the placenta and that of the fetus do not coincide, due to processes such as chromosomal mosaicism confined to placenta. These situations of discrepancy between the information of the placental cells and those of the fetus can cause a false diagnosis, and that is why techniques based on circulating fetal DNA are called screening techniques and not genetic diagnosis. In the case of amniocentesis, the chromosomal status of the fetus is directly studied and, in addition, not only a selected group of chromosomes are studied, but all the chromosomes thereof. For these reasons, in the case of an NACE with abnormal results, it is recommended to perform amniocentesis to confirm the results in cells directly from the fetus.
So that, In the short term, amniocentesis will continue to be performed in those cases in which a screening test such as the NACE of an altered result (as a confirmation technique) and also in those cases in which the doctor suspects that the fetus may have some alteration for any of the chromosomes that are not analyzed in the NACE test, in those cases in which the doctor observes ultrasound malformations so serious that directly decides to perform an invasive technique, or in those few cases where it is impossible to perform the NACE test because of the characteristics of the sample (altered karyotype of the mother, clinical conditions that interfere with the technique, etc).
What is the cost of the NACE and NACE Expanded test?
The NACE test, conducted entirely in Spain, has a cost of 545 euros. The NACE Expanded test, with the additional study of chromosomes 9 and 16, plus the 6 most prevalent microdeletions in prenatal development, costs 725 euros.
We thank Miguel Milan again for answering our questions and we hope that this information has been good for future moms.
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