At LIFE CODE we specialize in invasive prenatal diagnostic examinations. We apply all modern methodologies of analysis such as Next Generation Sequencing (NGS) for the analysis of all Exons of the Human Genome (WES), Molecular Karyotyping, as well as Conventional Cytogenetic analysis.
Invasive prenatal testing is performed by chorionic villus sampling (CVS) during the 11th–14th week of pregnancy, where a thin needle is inserted into the uterus to obtain a small sample from the placenta, or by amniocentesis after the 16th week, where amniotic fluid is obtained through a needle.
The sample obtained from these invasive methods is used for genetic analysis, selecting the appropriate diagnostic tests depending on the reason for referral.
Invasive methods are associated with a very small increase in the risk of miscarriage in the days following the procedure, at a rate of 0.01%–0.07%.
Invasive Prenatal Diagnostic Testing
Why is prenatal testing important?
It examines the fetus, thereby reducing the couple’s anxiety.
It provides different options for couples at high risk of having a child with an anomaly.
It allows couples at high risk for a specific genetic disease to proceed with pregnancy while having the option of prenatal testing of the fetus.
It enables couples to be psychologically prepared for the birth of a child with an anomaly and helps with delivery management as well as neonatal care.
It allows prenatal therapy of the fetus in cases where this is indicated.
Testing
A. Conventional Cytogenetic Analysis:
B. Molecular Karyotype (CMA)
Molecular karyotype, or Comparative Genomic Hybridization with Microarrays (array-CGH), has been introduced in both postnatal and prenatal analysis and aims to significantly improve the diagnostic rate of genetic anomalies leading to structural and functional abnormalities.
This method compares the DNA copy number of a reference (control) genome with that of the test genome, applying them to a microscope slide on which small DNA fragments covering the entire genome are immobilized. The main advantage of molecular karyotyping is its ability to detect any quantitative DNA changes, such as aneuploidies, deletions, and duplications, with analytical power 10–10,000 times higher than conventional karyotyping, depending on target size, coverage, and probe density.
However, it is limited in that it cannot detect:
- Balanced rearrangements, and
- Low-level mosaicism,
which currently do not allow it to replace conventional karyotyping in prenatal diagnosis.
It should be noted that in high-risk pregnancies or in the presence of ultrasound findings/anomalies of the fetus, molecular karyotyping detects significant conditions in about 8%–15% more cases than conventional karyotyping. Similarly, in low-risk pregnancies with a normal fetal karyotype, the rate of pathological findings revealed by molecular karyotyping ranges from 1.5%–3%.
Turnaround time: 7 working days
The test is accredited according to ISO 15189:2022 by the Hellenic Accreditation System (ESYD).
C. Molecular Genetic Analysis of Inherited Diseases:
Molecular diagnosis of Hemoglobinopathies:
β-Thalassemia and Sickle Cell Anemia
Molecular diagnosis of Cystic Fibrosis
D. Whole Exome Sequencing (WES)
Whole Exome Sequencing (WES) is a modern sequencing method based on Next Generation Sequencing (NGS) technology. It involves sequencing the exons of approximately 20,000 protein-coding genes, which represent about 1–2% of the human genome. These regions harbor about 85% of pathogenic genetic variants responsible for rare genetic disorders.
The WES test detects hundreds of variants, whose significance is evaluated according to the guidelines of the American College of Medical Genetics and Genomics (ACMG).
When the result of fetal WES is pathological, Genetic Counseling by a Medical Geneticist or Genetic Counselor often follows, in order to discuss the significance of the findings and further pregnancy-related options.
Turnaround time: 30 working days
The test is accredited according to ISO 15189:2022 by the Hellenic Accreditation System (ESYD).