Fetal Chromosomal Abnormalities

Screening for fetal chromosomal abnormalities is an essential part of prenatal care, especially for the high-risk mother. The most common chromosomal abnormalities are Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18) and Patau syndrome (Trisomy 13).

Down Syndrome (Trisomy 21) is associated with mild to moderate intellectual disabilities and may also lead to digestive issues and congenital heart defects. It is estimated that Trisomy 21 occurs in one out of every 740 newborns.

Edwards Syndrome (Trisomy 18) is due to an extra copy of chromosome 18, which is associated with a high rate of miscarriage. Infants born with Trisomy 18 often have congenital heart defects as well as various other medical conditions, shortening their lifespan. It is estimated that Trisomy 18 occurs in approximately one out of every 5,000 newborns.

Patau Syndrome (Trisomy 13) is due to an extra copy of chromosome 13, which is associated with a high rate of miscarriage. Infants born with Trisomy 13 usually have severe congenital heart defects and other medical conditions, and survival beyond the first year is rare. It is estimated that Trisomy 13 occurs in approximately one out of every 16,000 newborns.


About iGene®

iGene® is a revolutionary non-invasive prenatal blood test that can detect fetal chromosomal abnormalities such as Down syndrome, Edward syndrome and Patau syndrome with more than 99% accuracy. The test is expected to drastically change the course of prenatal screening because it offers expectant mothers accurate results without the risk of miscarriage. It is anticipated that the use of iGene® as a prenatal screening tool can reduce the rate at which invasive amniocenteses are performed, by as much as 95%.

Using Next-Generation sequencing technology called Whole Genome Sequencing (WGS), scientists can now analyse cell-free fetal DNA extracted from a maternal blood sample and determine the presence of aneuploidies such as trisomies and deletions. This is followed by an in-depth bioinformatics analysis of fetal DNA ratios. iGene® is able to detect Trisomies 21 (Down Syndrome), 18 (Edward Syndrome) and 13 (Patau Syndrome) with more than 99% accuracy.

iGene® has a high detection rate of more than 99%, with a false positive rate of 0.05% and false negative rate of 0.003%, rendering it one of the most accurate screening tests compared to other non-invasive screening tests.

TABLE 1. Comparison of the DR, FPR ,FNR of current fetal trisomy screening strategies.

Test Detection Rate (%) False Positive Rate (%) False Negative Rate (%)
iGene® >99 0.05 0.003
Nuchal Translucency 70 5 30
First Trimester Screen 84 < 5 16
Triple Test < 70 5 > 30

Clinical Studies

iGene® has been clinical validated on the largest study to date, with over 146,000 samples¹. The sample size of over 146,000 is important to make credible inferences about its efficacy in average risk pregnancies. iGene® delivers high positive predictive values compared to other NIPT tests. In practice, a test designed using a small sample size would result in large confidence intervals.

1. Zhang H, et al. 2015 Ultrasound Obstet. & Gynecol. 45:530-538.

For more information, please go to iGenePrenatalTest.com

Who Is Eligible?

iGene® is suitable for pregnant women at 10 weeks gestation and above.

Women with associated risks such as increased maternal age or with any of the following conditions, can also choose to undergo the test.

  • Age 35 and above
  • Abnormal ultrasound results.
  • A family history of an inherited condition
  • A previous pregnancy with a fetal abnormality

Patients who get a screen positive result are offered genetic counseling and asked to undergo invasive testing such amniocentesis or chronic villus sampling (CVS) to confirm the diagnosis.

iGene Diagnostics


iGene Diagnostics is a wholly owned subsidiary of INEX Innovations Exchange Pte Ltd, a pioneering healthcare and diagnostics company focused on creating and developing innovative technologies for the advancement of women’s health, including maternal and fetal health.

iGene Diagnostics has set up a Singapore Next Generation Sequencing (NGS) clinical laboratory based on the leading sequencing Life Technologies platform (Ion Proton) to offer Non Invasive Prenatal Testing (NIPT) services.

Our deep commitment to Next Generation Sequencing bridges the gap between genomic data and health outcomes by delivering actionable results to improve clinical decisions and empower women to make informed decisions.

The state-of-the-art iGene sequencing laboratory in Singapore enables the analysis of NIPT samples from start to end, from sequencer through data analysis and report management. iGene Diagnostics is supported by a team of experienced technical staff and scientists.

iGene Diagnostics Laboratory Capabilities:

  • End to End NIPT sample processing, from sample preparation, sequencing to bioinformatics analysis
  • Quick turnaround time of 7-10 business days
  • Experienced technical and scientific support to interpret results
  • Rigorous quality control in the Next Generation Sequencing workflow



VIDEO iGene®