NIFT Standard by GenePlanet is a noninvasive prenatal test (NIPT) designed to analyze fetal DNA circulating in maternal blood to detect chromosomal abnormalities early. The test uses next-generation sequencing (NGS) and advanced bioinformatics to identify extra or missing copies of specific chromosomes associated with genetic syndromes. This method eliminates the risks associated with invasive diagnostic procedures such as amniocentesis or chorionic villus sampling (CVS) while maintaining high accuracy in chromosomal analysis.
The test uses a maternal blood sample, typically collected as early as the 10th week of pregnancy. Fetal DNA originates from the placenta and is extracted from maternal circulation. It is then analyzed to determine the fetus's chromosomal composition. Using massively parallel sequencing (MPS), millions of DNA fragments are sequenced and computationally aligned to detect deviations from the expected chromosomal count. Bioinformatics tools differentiate between maternal and fetal DNA, ensuring precise measurements even when the fetal fraction is low.
Scope of Analysis: Beyond Basic Aneuploidy Detection
NIFT Standard by GenePlanet screens for the most common trisomies, including:
- Trisomy 21 (Down Syndrome): Caused by an extra copy of chromosome 21, this condition leads to developmental delays, characteristic facial features, and varying degrees of intellectual disability. Down syndrome is one of the most frequently occurring chromosomal disorders, affecting approximately 1 in 700 live births.
- Trisomy 18 (Edwards Syndrome): A severe genetic disorder caused by an extra copy of chromosome 18, resulting in profound developmental delays, congenital heart defects, and a high neonatal mortality rate. This condition occurs in approximately 1 in 5.000 live births.
- Trisomy 13 (Patau Syndrome): A rare but severe disorder caused by an additional chromosome 13. It is associated with multiple congenital anomalies, brain malformations, cleft palate, and severe cardiac defects. The prevalence is approximately 1 in 10.000 live births.
Unlike basic non-invasive tests, the NIFT Standard expands its scope to include sex chromosome aneuploidy detection, which provides insights into abnormalities affecting the X and Y chromosomes. The test screens for conditions such as:
- Turner Syndrome (45, X): A disorder in females where one of the X chromosomes is missing or partially missing, leading to short stature, ovarian dysfunction, and cardiovascular abnormalities.
- Klinefelter Syndrome (47, XXY): A condition in males with an extra X chromosome, which may result in tall stature, delayed speech development, and infertility.
- Triple X Syndrome (47, XXX): A condition in females caused by an additional X chromosome, typically associated with mild learning difficulties and delayed speech and language development.
- Jacob’s Syndrome (47, XYY): A condition in males with an extra Y chromosome, often linked to tall stature and a slightly increased risk of learning and behavioral difficulties.
Scientific Methodology: Precision Through Genomic Sequencing
The accuracy of the NIFT Standard is ensured through whole-genome sequencing and bioinformatics analysis, which quantify the proportion of DNA fragments corresponding to each chromosome. The test utilizes:
- Massively Parallel Sequencing (MPS): This method simultaneously sequences millions of DNA fragments, allowing for a highly detailed genetic profile.
- Fetal Fraction Analysis: By measuring the percentage of fetal DNA in maternal blood, the test improves reliability and minimizes the risk of false positives or negatives.
- Computational Variant Calling: Advanced bioinformatics algorithms compare observed DNA fragment distributions against reference human genome databases, identifying deviations suggestive of chromosomal abnormalities.
Unlike conventional karyotyping or fluorescence in situ hybridization (FISH), which require fetal cell culture and are invasive, the NIFT Standard provides a highly accurate, risk-free alternative. The test’s sensitivity and specificity for trisomy 21 exceed 99%, while detection rates for trisomy 18 and trisomy 13 range from 96% to 99%.
Clinical Significance and Applications
NIFT Standard is particularly beneficial in pregnancies with:
- Increased maternal age, where the risk of chromosomal abnormalities is higher.
- Abnormal ultrasound findings suggest a potential genetic disorder.
- A history of chromosomal disorders in previous pregnancies.
- Parental chromosomal translocations may predispose the fetus to aneuploidies.
- Reassurance for expectant parents, even in cases where there is no known genetic risk.
By offering a broader scope of chromosomal screening, the NIFT Standard aids in early detection and informed decision-making, ensuring that pregnancies at risk of chromosomal abnormalities are identified with high precision. The test represents an essential advancement in prenatal genetic screening, combining the power of modern genomics with the safety of non-invasive methodologies.
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