Prenatal ExomeXtra® is designed for genetic diagnostics prior to birth — combining the full analytical power of ExomeXtra® with comparative trio analysis of fetus and both parents. It is indicated in two clinical scenarios: for pregnancies with conspicuous ultrasound findings, where it identifies the genetic cause of fetal structural anomalies, and for pregnancies without ultrasound findings, where prenatal genetic diagnostics enables early identification of severe early-onset conditions.
Is your patient insured in Germany? Our colleagues at the Zentrum für Humangenetik Tübingen will gladly support you!
The Benefits of Our ExomeXtra® at a Glance
Our Promise to You
Service Details
Scope of Analaysis
- All coding regions
- >46,000 non-coding disease-associated regions (deep intronic, regulatory)
- Non-coding RNA genes
- Mitochondrial genome (mtDNA)
- Upstream splice sites
- Mosaic variant detection
- Genome-wide CNV detection
- Uniparental disomy (UPD) analysis — for pregnancies with conspicuous findings
- Inheritance pattern analysis — de novo, compound heterozygous, X-linked, parental mosaicism
- Special analysis for mildly affected parents — reduced penetrance, variable expressivity, imprinting effects
- Prenatal screening for relevant infections
Medical Report Includes
- All relevant variant types: sequence variants (SNV, indel), small copy-number variants (CNV), and large aneuploidies – including mosaic variants
- Variants of ACMG classes 3, 4, and 5 — classified and interpreted in the context of your patient’s phenotype
- Pathogenic and likely pathogenic variants outside the primary gene panel — evaluated for clinical relevance to early-onset childhood disorders
- Direct recommendations for clinical management and further testing, where applicable
- Assessment of genetic relevance for family planning
Optional Add-On Services
- Analysis of all ACMG genes
- HLA typing
- Pharmacogenetic analysis including dosing information
Sample Report
Our Standard Sample Requirements
For the Fetus:
- amniotic fluid (native or cultured)
- chorionic villi (native or cultured)
- extracted fetal DNA
- abortion material
For the Parents:
- 1 ml–2 ml EDTA blood (recommended sample type)
- genomic DNA (1 µg–2 µg)
- DBS cards, buccal swabs, or saliva are also possible
Here you can find more information on how to ship your sample safely.
If prenatal trio exome diagnostics is not possible, we still need a sample from the mother to test for maternal cell contamination (MCC). Other sample material sources are possible on request. Please note: In case of insufficient sample quality, the analysis might fail. If you have more than one option of samples, please contact us (diagnostic-support@cegat.com), and we will assist you in choosing the optimal sample for your patient.
The Diagnostic Benefit of Trio Analysis in a Prenatal Setting
Sequencing the fetus alongside both parents enable inheritance analysis across all target regions — identifying de novo variants, compound heterozygous constellations, and inheritance patterns that single-sample analysis cannot detect. Our adaptive strategy additionally accounts for reduced penetrance, variable expressivity, and imprinting effects. UPD analysis is included for pregnancies with conspicuous ultrasound findings.
With Conspicuous Ultrasound Findings
Prenatal ExomeXtra® is used to determine the genetic cause of disease in a fetus with abnormal ultrasound findings. In addition, we investigate the risk of serious health complications in the early stages of the child‘s life. The comparative analysis of fetus and both parents increases the probability of identifying disease-causing variants.
Prenatal ExomeXtra® enables the detection of variants that affect metabolism, for example, and offers the possibility of initiating treatment immediately after birth. Our unique analysis approach also allows the detection of variants with imprinting effects, variable expressivity, and reduced penetrance.
In our own cohort of over 1,500 pregnancies with abnormal ultrasound findings, a disease-causing variant was identified in 38% of cases.
Without Ultrasound Findings
Prenatal ExomeXtra® can also be performed when ultrasound findings are inconspicuous. A study by Sukenik-Halevy et al. shows that more than 50% of cases with postnatal neurocognitive disorders showed no prenatal ultrasound abnormalities.1
We have compiled a comprehensive panel of over 2,000 genes associated with severe early-onset diseases. After trio exome analysis and filtering, we screen all genes in the panel for pathogenic and likely pathogenic variants (ACMG class 4, 5) associated with severe, early-onset disease. Our experts also report all pathogenic and likely pathogenic variants outside this gene panel and discuss their clinical relevance if they lead to severe childhood disorders.
Prenatal Infection Screening
Certain infections cause symptoms that resemble genetic conditions — and would not be detected by standard genetic testing. Every Prenatal ExomeXtra® analysis includes targeted screening for Toxoplasmosis, Varicella, CMV, Fifth disease, Syphilis, and Herpes Simplex 1 & 2 as a differential diagnosis. Findings are reported alongside the genetic results.
References
1 Sukenik-Halevy, R. et al. The prevalence of prenatal sonographic findings in postnatal diagnostic exome sequencing performed for neurocognitive phenotypes: A cohort study. Prenatal diagnosis 42, 717–724; 10.1002/pd.6095 (2022).
Further Information
Study: Prenatal Trio Exome Sequencing Clarifies Ultrasound Abnormalities with a Solution Rate of 38%. Continue reading
Identifiy the disease-causing alteration in a fetus
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Diagnostic Support
We will assist you in selecting the diagnostic strategy – for each patient.
