Launch of cffDNA or NIPT testing in Iran under the license of Premaitha UK

Launch of cffDNA or NIPT testing in Iran under the license of Premaitha UK


What is NIPT?
The NIPT [1] test, or non-invasive screening test, also called cell free fetal DNA [2], is a prenatal screening test for common chromosomal abnormalities (such as trisomy 21, 18, and 13) and sex determination from week 10 of pregnancy. is. Each person normally has two pairs of chromosomes, and each chromosome is made up of circular DNA strands that contain thousands of genes. Trisomy is a condition in which instead of two copies of a single chromosome, there are three copies, resulting in severe mental and physical disorders.

Without a prenatal diagnosis, in the United States alone, we should expect to have more than 7,000 children with Down syndrome each year, more than 1,000 trisomy 18 and 600 trisomy 13 in total 4.25 million births.


NIPT test history

The use of free DNA in maternal blood flow of fetal origin has been discussed since 1997. The source of cffDNA is a pair of trophoblast cells that enter the mother's bloodstream following the scaling of these cells and make up 3-13% of the total free DNA in the mother's bloodstream. CFDNA appears in the mother's blood during the 7th week of pregnancy and is removed from the baby's bloodstream immediately after birth, so that it cannot be detected in the mother's blood for another 2 hours after delivery.

NIPT test applications
1- Determination of chromosomal disorders such as Down syndrome (trisomy 21), Edward syndrome (trisomy 18) and Pato syndrome (trisomy 13).

2- Sex determination in cases where there is a possibility of inheriting genetic disorders related to X or L-Linked chromosomes or the possibility of genetic disorders related to Y or L-Linked chromosomes.

The leading causes of these disorders are Fragile X Syndrome [4], Duchenne Muscular Dystrophy [5] and Hemophilia. This means that if a mother carries a disease that is related to the X chromosome, it can be transmitted to her son's fetus, and it is possible for her sons to develop the disease.

Therefore, if we can detect a male fetus faster in this method, we can design the genetic counseling and, if necessary, the required genetic tests.

If the father of the family carries genes that are related to disorders of the Y chromosome or Y-Linked Disorders, they will also be candidates for genetic counseling or genetic testing during pregnancy. Famous examples of these disorders include:

Infertility associated with the Y chromosome or Y chromosome infertilty (there is a defect in the Y chromosome that can cause azoospermia or oligosospermia).

- Abnormal or Absent Testicular Development disease (defect in the sex-determining area Y = SRY).

Retinitis pigmentosa, which is called the RPY (retinitis pigmentosa, Y-linked) gene, is located on the Y chromosome and is defective.

Sex determination is also important in diseases that are not dependent on sex chromosomes, but gender also plays an important role in the development of a number of important symptoms. A well-known example is congenital adrenal hyperplasia, in which the production of androgen hormones increases due to inhibition of the production of corticosteroids, and if the fetus is a girl, it causes the external genitalia to become masculine.

In these cases, treatment with dexamethasone should be started at 7 weeks of gestation for female fetuses and prevent the release of androgens.


Who are the candidates for the NIPT test?
According to the joint recommendation of the American Association of Obstetricians and Gynecologists and the Association of Maternal and Fetal Medicine in 2015 and the International Association of Pregnancy Screening in 2014, this test can be recommended to the following groups:

Women 35 years or older
A positive screening test (such as first, second, integrit, or sequential screening tests).
Ultrasound findings show an increased risk of chromosomal abnormalities.
Previous history of fetal or child with common trisomy
Family history of trisomy 21, 18 and 13
Failure to perform routine screening tests until 22 weeks of age for any reason or the presence of an abnormal ultrasound finding from 22 weeks onwards
However, according to the findings of the Nilo Laboratory, the best group to perform this test are the high-risk groups in the first and second trimester screening protocols. In high-risk groups, the following test can be used as a pre-test before performing diagnostic tests:

- Women who are very afraid of sampling diagnostic tests such as amniocentesis or CVS,

- Women who are not at risk of miscarriage of diagnostic tests,

- Women with a history of recurrent miscarriage (three or more than three miscarriages under 20 weeks of age or fetal weight below 500 g)

- Women who have a history of ruptured bladder,

- Women who have golden fetuses (fetuses that are formed after several years of infertility, parents of advanced age or resulting from IVF pregnancy).


Sample required for NIPT testing
10 ml of blood from the mother taken in anti-coagulation containing EDTA.

Test conditions
Minimum gestational age is 10 weeks
Single pregnancy
Pregnancy caused by IVF or rented uterus
Cell culture in amniocentesis is not successful for any reason (the sample is contaminated with the mother's blood or the gestational age is more than 20 weeks).

Note 1: This test is not recommended for pregnant women with cancer or women with a history of bleeding over the past 12 months.

Note 2: According to a meta-analysis conducted in 2016 by Dr. Philip Taylor et al., It was found that the detection power of the NIPT test in twin pregnancies is reduced compared to one twin. This reduction is 21 to 9% in trisomy, 18 to 28% in trisomy, and 13 to 22% in patu or trisomy syndrome.

Note 3: In twin pregnancies, there is not enough evidence to determine the effectiveness of the NIPT test (as is the case with all brands), but preliminary findings indicate that the test is highly accurate in twins.

Note 4: In no case should this test be requested for triple or higher.


NIPT test
Each person normally has 23 pairs of chromosomes, and each chromosome is made up of a ring-shaped structure (DNA) that contains genes. In each chromosome there are certain sequences or sequences of DNA molecules that are specific to each chromosome (for example, 21q22 or region 2 of band 2 of the long arm of chromosome 21 are sequences or sequences specific to chromosome 21 and as Hot Spot or Important Chromosome 21 is used to detect chromosome 21).


The NGS method can be used to calculate the exact amount of each chromosome by counting the number of these sequences, so that the total chromosome 21 in the mother's blood can be compared to other chromosomes. This ratio is always equal to one in a pregnant mother containing a normal fetus.

If the fetus has Down syndrome, the sequence of chromosome 21 sequences is much smaller, and therefore more than other chromosomes, and the ratio is higher than one.


NIPT test interpretation
The results are reported in three low-risk, high-risk, and ineffective forms:
Low risk: Indicates that more than 99 percent of fetuses are at risk for chromosomal disorders 21, 18, and 13.
High risk: It is likely that more than 99% of fetuses are at high risk for chromosome 21, 18, and 13 chromosomal abnormalities, and an invasive diagnostic test such as amniocentesis should be performed to confirm the answer.
No results: In very rare cases, due to insufficient cffDNA levels in the mother's blood (due to the mother's high weight or low fetal age), the test does not work and we need to take blood again.

Advantages of NIPT testing

The NIPT test has the following advantages over other screening tests:

Less Positive False: The false positive probability of this test is below one percent for trisomies 21, 18 and 13.
Higher diagnostic power: Due to the separation of free DNA in the maternal circulatory system (cffDNA) from the free DNA of maternal origin (cfmDNA) performed in this method, the diagnostic power is above 99% for disorders of chromosomes 21, 18 and 13 arrives.
High accuracy of sex determination: The detection power of sex in this method is over 97%, which is higher than many similar tests.
Absence of the possibility of miscarriage: Unlike invasive diagnostic methods, because this test is performed only on the mother's blood, there is no risk of miscarriage.
Ineffectiveness of previous pregnancies: Since the half-life of cffDNA is less than 2 hours, previous pregnancies do not interfere with the test result.
Early diagnosis: This test can be done from the 10th week of pregnancy.
Quick response: The answer will be ready between 3 and 7 working days after sampling.
The best screening protocol after the 22nd week of pregnancy


Note: It should be emphasized to patients that one of the limitations of this test is that the residual risk after a negative NIPT test followed by a positive screening test is about 2%.

Finally, it should be noted that this test is only a high-diagnostic screening test and can never be a substitute for diagnostic tests. The test is currently being developed in Iran under the license of the British company Premaitha and under the brand name IONA, and the answer will be ready in 3 to 6 working days.


[1]. Non Invasive Prenatal Testing (= NIPT)

[2]. cell free fetal DNA (= cffDNA)

[3]. sex determination for X-linked genetic disorders

[4]. fragile X syndrome

[5]. Duchenne Muscular Dystrophy

[6]. Congenital Adrenal Hyperplasia

[7]. Parental balanced robertsonian translocation