General information about VeriSeq NIPTiva v2 test

The human body is composed of trillions of cells. Each cell has a nucleus where chromosomes are located. Chromosomes are the most important components of the nucleus because they contain genetic information for the development and function of the organism. Human cells contain 23 pairs of chromosomes (a total of 46 chromosomes). Half of these 46 chromosomes come from the mother and the other half from the father. Chromosomes contain our genetic material with all the information necessary for proper development and function of the organism. Pairs of chromosomes 1 to 22 are called autosomes, and the 23rd pair is known as the sex chromosomes (XX in females and XY in males).
NIPTiva is a safe and reliable screening test for detecting fetal genetic abnormalities at the genome level from peripheral blood samples of women who are at least 10 weeks pregnant. The blood sample contains a certain percentage of fetal DNA fraction, from which a complete analysis is performed using next-generation sequencing (NGS) technology. Compared to traditional biochemical screening tests, NIPT provides significantly higher sensitivity and specificity (99.9%), and a significantly more comprehensive approach to analyzing genetic abnormalities. Most importantly, NIPTiva testing significantly reduces the number of invasive procedures in normal, or regular pregnancies.

Prenatal tests

Autosomal aneuploidy
The term trisomy is used to describe the presence of three chromosomes instead of the usual pair, or the presence of an extra chromosome. The most common autosomal aneuploidies are:
Trisomy 21 (also known as Down syndrome) occurs in approximately 1 in 700 births, and the risk increases with maternal age. It often results in mental disorders and physical malformations, particularly heart defects.
Trisomy 18 (Edwards syndrome) andtrisomy 13 (Patau syndrome) occur in approximately 1 in 7,000 births. The risk also increases with maternal age. These trisomies are associated with severe mental and physical disorders.

Aneuploidy of sex chromosomes
Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The presence of changes in the sex chromosomes represents aneuploidy of sex chromosomes. These changes can have different consequences, such as the development of malformations, cognitive disorders and growth disorders, as well as sexual problems and infertility.
Klinefelter syndrome: affects males (about 1 in 500 to 1,000) and is caused by the presence of an extra X chromosome (47, XXY). The risk increases with the mother's age. Those affected by this trisomy usually have increased height, sometimes mild mental disorders and fertility problems.
Jacob syndrome: affects males (about 1 in 1,000) and is caused by the presence of an extra Y chromosome (47, XYYY). Affected individuals are taller than normal, may have some speech delay, and generally do not have mental disorders.
Turner syndrome: affects females (about 1 in 2,500) and is characterized by the lack of an X chromosome (45, X0). People with this monosomy have short stature, infertility, and sometimes heart and kidney disorders.
Triple X syndrome: affects females (about 1 in 1,000) and is characterized by the presence of an extra X chromosome (47, XXX). Many girls and women with triple X syndrome have no or only mild symptoms. In other cases, symptoms may be more serious and may include developmental delay and learning difficulties.

What are aneuploidies?

Aneuploidy is a condition in which there is an extra chromosome or one or more chromosomes are missing. Since each chromosome contains hundreds of genes, an extra or missing chromosome disrupts the existing balance in cells and, in most cases, is not compatible with life.

What are the most common aneuploidies?

The most common aneuploidies in humans are trisomies, which make up about 0.3%. The most common aneuploidies are Down syndrome (occurring in 1 out of 700 births), followed by Klinefelter syndrome (occurring in 1 out of 1,000 births).

What are autosomal aneuploidies and sex chromosome aneuploidies?

One way to classify aneuploidy is according to the type of chromosome affected: autosomal chromosomes (pairs 1 to 22) and sex chromosomes (pair 23, X and Y).

What are microdeletions?

Microdeletions are abnormalities that occur when a portion of a chromosome is missing. The effect of a microdeletion on the health and development of the fetus depends on its location and size. Some microdeletions can cause intellectual difficulties, motor skill problems, or miscarriage, while others do not harm at all.

How common are microdeletions?

Unlike other chromosomal abnormalities, which are more likely to occur in mothers with certain risk factors (such as those who are 30 or older or who have a family history of genetic disorder), microdeletions appear to occur randomly and equally affect any baby, regardless of other risk factors.

How are fetal aneuploidies detected during pregnancy?

There are different prenatal tests for detecting fetal aneuploidy, which are generally divided into two main groups: noninvasive and invasive. Noninvasive prenatal testing poses no risk to the fetus and mother, as it only requires a sample of the mother's blood. It can be done from the 10th week of pregnancy and is much more reliable than the combined screening test, which has a higher error rate. Invasive tests are chorionic villus sampling and amniocentesis. Regarding the detection of aneuploidy, they are only done to confirm suspicion of aneuploidy detected by noninvasive prenatal testing, as they carry a risk of miscarriage between 1% and 2%.

Niptiva prenatal test

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