Rainbow Clarity™ Rapid Prenatal Trio Whole Genome Sequencing Test

Introduction

Fetal abnormalities are identified in approximately 3% to 5% of pregnancies, and are responsible for 20% of perinatal deaths. When structural abnormalities are identified from fetal ultrasound, physicians usually order karyotype and clinical microarray (CMA) tests as a first line of diagnostic approach, to determine if a genetic etiology is associated with the abnormal ultrasound features.

However, karyotyping and microarray based testing returns a positive diagnosis for only about 20% of cases, and the other, approximately 80% of the cases, remain unresolved.

Recent publications suggest that diagnostic whole exome or whole genome tests can detect pathogenic gene variants in a substantial proportion of these remaining resolved cases.

The Rainbow Clarity™ Rapid Trio Whole Genome Sequencing Test is a prenatal diagnostic test. The test is processed using cells from the fetus obtained through amniocentesis or chorionic villus sampling (CVS). CVS is a procedure in which amniotic fluid and cells are taken from the uterus for testing.

  • Whole genome sequencing at 45x-50x sequencing depth is used for the fetal sample. The even sequence coverage delivered by whole genome sequencing at 50x depth provides high sensitivity for detection of gene variants associated with a number of well-characterized fetal disorders.

  • With trio sequencing analysis, de novo and compound heterozygous mutations can be readily confirmed, and parental inheritance can also be analyzed to increase the confidence of a diagnosis.

Emergency Testing

  • With a rapid 1 to 1.5 week turnaround time, physicians can use this whole genome sequencing test early in the second trimester if karyotying or microarray test failed to provide a positive result

Test Descriptions

  • DNA obtained through amniocentesis or chorionic villus sampling

  • Physicians can choose to obtain amniotic fluids as early as week 16 of the pregnancy

  • Rapid trio whole genome sequencing is performed at a U.S. CAP-accredited and CLIA-certified laboratory

Diagnostic Test Report

  • This is a diagnostic analysis based on the fetus' symptoms and family history

  • Rainbow's Triple Clinical Interpretation Analysis will be performed by experts in the U.S. and Japan

    1. First-round clinical interpretation is performed by U.S. board-certified clinical geneticists

    2. A second clinical interpretation is performed by the medical team at the Center for Intractable Disease Research at Japan's Juntendo University Medical School (Tokyo)

    3. A third clinical analysis will be performed using multiple bioinformatic platforms including U.S.-based Fabric Genomics’ and U.K.-based Congenica’s algorithms and analytics

  • Duplication, insertion, deletion and single-nucleotide variants will be analyzed

  • Copy Number Variation (CNV) report including chromosomal aneuploidies, microdeletions and microduplications at >30kb resolution can also be ordered by the physician. The report content is similar to that obtained from Clinical Microarray (CMA) testing

  • Structural variants (SV) will also be analyzed

  • Trio sequencing available - de novo mutations will be reported using trio analysis

Incidental Finding report

  • To preemptively determine the risks of developing over 100 birth defect-related disorders, over 600 genes that are known to be associated with these disorders will be screened

  • Screening of over 1600 genes associated with 1000 childhood-onset disorders can also be ordered by physicians

  • The report will include pathogenic and likely-pathogenic variants. No VUS will be reported

Is This Test Right For You?

  • If you are a pregnant woman who has undergone amniocentesis to detect fetal chromosomal abnormalities, and hope to rule out the possibility that the fetus has severe single gene disease, you may consider receiving this prenatal test.

  • If your physician has found an abnormality in the fetal ultrasound, and would like to determine if a genetic disease is associated with the abnormality, this test may be appropriate for you.

    1. In addition, the physician would also like to rule out the possibility that the fetus is suffering from a range of serious single gene diseases, the physician may order an incidental finding report.

  • For couples who have evidence (family history, affected siblings, etc.) that the fetus is at high risk of developing a genetic disease, they may want to discuss with their physicians about taking this test.

We provide free referrals to physicians with substantial clinical genetic experience for pre- and post-test consultation.