Choice in prenatal diagnostic testing
Prenatal diagnostic testing—through the use of Reveal® microarray or one of the many additional diagnostic tests offered by Integrated Genetics—can provide further clarity for patients with a variety of indications including:
- A positive result through NIPT or serum screening
- An ultrasound that may show structural abnormalities
- A family history of chromosomal imbalances
- Routine analysis that shows the presence of an abnormality
- Amniocentesis or CVS performed for any other indication
The choices we offer in diagnostic testing—in addition to the choices we offer in carrier screening, NIPT, serum screening, and hereditary cancer testing—help us to offer unparalleled continuity of care to your patients.
Reveal cytogenetic microarray
Reveal® SNP microarray is a high-density copy number array that detects genomic imbalance related to congenital anomalies, ultrasound abnormalities, miscarriage, and stillbirth. In fact, according to a practice bulletin issued by The American College of Obstetricians and Gynecologists (ACOG), "chromosomal microarray analysis should be recommended as the primary test (replacing conventional karyotype) for patients undergoing prenatal diagnosis for the indication of a fetal structural abnormality detected by ultrasound examination."1
It can also detect copy neutral changes, such as uniparental disomy (UPD) and consanguinity, both of which are associated with increased risk for autosomal recessive conditions.
Specimen types include amniotic fluid, chorionic villi, POC, and cord blood.
Chromosome analysis (amniocentesis/CVS)
Prenatal chromosome analysis is also available. A recent practice bulletin issued by ACOG also recommends that "all pregnant women should be offered prenatal assessment for aneuploidy by screening or diagnostic testing regardless of maternal age or other risk factors."1
Other prenatal diagnostic testing options
Acetylcholinesterase (AChE) Testing: AChE is performed on an amniotic fluid sample to diagnose fetal open neural tube defects and some ventral wall defects.
Angelman/Prader-Willi Syndromes Methylation Assay: Angelman syndrome is characterized by severe developmental delay/intellectual disability, absence of speech, ataxic gait, inappropriate laughter, hand-flapping, and less frequently, microcephaly and seizures. Prader-Willi syndrome is characterized by hypotonia, failure to thrive in infancy, rapid weight gain/obesity between 12 months and 6 years, characteristic facial features, hypogonadism and mild to moderate intellectual disability.
Amniotic Fluid Alpha-Fetoprotein (AFAFP) Testing: AFAFP analysis is used to screen for fetal open neural tube defects and abdominal wall defects.
Cytogenetics Products of Conception (POC) Chromosome Analysis: Indications for cytogenetic analysis on POC include: history of more than two miscarriages, abnormalities on ultrasound prior to pregnancy loss, confirmation of abnormal prenatal results or pregnancy loss after IVF.
Inheritest Gene-specific Sequencing, NGS: Sequencing reads are aligned with the hg19 build of the human genome reference sequence. Greater than 98% of target bases are covered at greater than or equal to 20x coverage. Analytical sensitivity for this assay is estimated to be >99%.
Maternal Cell Contamination Analysis (In-House Samples Only): Integrated Genetics requires a maternal blood sample to conduct maternal cell contamination testing in conjunction with all prenatal molecular testing. Both amniotic fluid and CVS may have maternal cells present in the sample.
Mutation-specific Sequencing (Prenatal): If a pregnancy is at increased risk for one of the genetic disorders on Inheritest or single gene testing because either both members of a couple are found to be carriers for mutations in a recessively inherited gene, or the woman is a carrier of one of the X-linked disorders, fetal testing can be performed on amniotic fluid, chorionic villi or cord blood to determine if the fetus is affected with the disorder in question (eg, cystic fibrosis, Tay-Sachs, etc.).
Pompe Disease Mutation Analysis: Indications for Pompe disease mutation analysis by sequencing include: Individuals with a family history or clinical characteristics of Pompe disease, or individuals who have tested positive for GAA deficiency by enzyme test or newborn screening assays.
Prenatal Noonan Syndrome Panel: Prenatal diagnosis for at-risk pregnancies when a parent is affected or when nuchal translucency, thickening or cystic hygroma or related abnormalities are seen on fetal ultrasound. We test for 9 genes associated with Noonan and Noonan-like syndromes.
Sickle Cell Anemia Mutation Analysis (Fetal): Sickle cell anemia is an autosomal recessive disorder that causes severe anemia. Molecular testing is available for prenatal testing for at-risk pregnancies (ie, both parents known to be carriers).
Zygosity Testing: Zygosity testing determines if the fetuses are monozygotic or dizygotic in a multiple gestation pregnancy. Zygosity testing might be desired in cases when ultrasound identifies a discordance between fetuses in a multiple gestation.
- ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders, Obstet Gynecol. 2016 May;127(5):e108-22