Presentation: Fetus with a diaphragmatic hernia

A woman attends her routine fetal anomaly scan at 20 weeks, at which the sonographer identifies an anomaly in the chest. The stomach appears to be partially above the diaphragm, protruding into the chest cavity and the heart appears pushed towards the baby’s right side. The sonographer suspects a congenital diaphragmatic hernia (CDH) and refers to antenatal clinic for ongoing management. 

• If a CDH is identified on ultrasound, an amniocentesis or chorionic villus sample should be considered to allow for genomic testing.
• Around 30% of CDH cases have a genetic cause. The chance is more likely where there are additional or associated anomalies.

• Refer to local guidance regarding fetal medicine referral. Further review in a fetal medicine unit is usually warranted. Women should also be referred for a fetal echocardiogram to assess the baby’s cardiac structure.
• A fetal medicine review will determine whether genomic testing is appropriate, and referral to clinical genetics will be considered.
• The relevant team will refer to the NHS England National Genomic Test Directory eligibility criteria to determine which tests are available for your patient. The directory itself provides a list of all available tests.
  • For those working within NHS Wales, please consult the All Wales Medical Genomics Service website for information on how to arrange testing.
• Decide which testing is most suitable for the specific clinical scenario and for your patient.
• Depending on the clinical scenario, a range of different genomic tests may be considered:
  • R22 Fetus with a likely chromosomal abnormality. This will process both:
    • genome-wide common aneuploidy testing; and
    • chromosomal microarray.
  • Where there are multiple or complex anomalies and/or above testing is non-diagnostic, fetal exome sequencing may be considered:
    • R21 Fetal anomalies with a likely genetic cause: fetal exome sequencing.
      • Referral to clinical genetics and/or multi-disciplinary discussion is required.
      • A record of discussion form is required.
  • For all DNA-based tests, an EDTA sample is required. For many of the tests (particularly whole genome and exome sequencing), parental samples are also needed or are helpful. Please refer to your local Genomic Laboratory Hub for details of test request forms and where to send samples.
  • If amniocentesis or chorionic villus sampling is performed, the samples should be sent in a plain container.
• Information about patient eligibility and test indications was correct at the time of writing. When requesting a test, please refer to the National Genomic Test Directory to confirm the right test for your patient.

For clinicians

• NHS England: National Genomic Test Directory

For patients

• Great Ormond Street Hospital for Children NHS Foundation Trust: Diaphragmatic hernia information
• Public Health England: Congenital diaphragmatic hernia (CDH) information for parents