Presentation: Patient with a previous pregnancy or baby affected by a genetic condition

A 24-year-old woman discloses at eight weeks pregnant that she had opted to terminate a previous pregnancy. In that previous pregnancy, a genetic condition was diagnosed at 15 weeks’ gestation following chorionic villus sampling.

• When a genetic condition has been identified in a previous pregnancy and a genetic variant has been identified.
• When there are structural anomalies or other concerning features in a current pregnancy.
• When there is a family history of a genetic condition.

• Consult the National Genomic Test Directory. From this directory you can access the rare and inherited disease eligibility criteria for information about individual tests and their associated eligibility criteria. You can also access a spreadsheet 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.
• To find out which genes are included on different gene panels, see the NHS Genomic Medicine Service (GMS) Signed Off Panels Resource.
• Collect a detailed family and personal history from the couple.
• Refer to clinical genetics for review by a clinical geneticist or genetic counsellor.
  • The clinical genetics team will consider which testing is most suitable for the patient or family. This may include testing previous pregnancies from which tissue and/or DNA is available. If a specific diagnosis is suspected, the parents may be offered testing.
• Refer to a consultant-led maternity unit for obstetric review. The couple may need referral to your local fetal medicine unit.
• If an invasive test is required in the current pregnancy, an amniocentesis or chorionic villus sample or fetal blood sample (in a puple-topped EDTA tube) 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.
• A record of discussion form, or another appropriate local consent form, is required for testing.
• 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

• Antenatal Results and Choices (ARC)
• Genetic Alliance UK