We provide a comprehensive prenatal diagnostic service that can be performed on either amniocentesis or chorionic villus samples. The testing approach is tiered depending upon the indication for testing.
All prenatal referrals are analysed by QF-PCR to detect targeted aneuploidies (e.g. trisomy 21 Down syndrome).
Referrals presenting with abnormalities detected on ultrasound scan or a nuchal translucency >=3.5 mm are provided with a high-resolution analysis for genomic imbalances by array-CGH.
Prenatal diagnosis for molecular genetic disorders is available for referrals that have had appropriate preparatory investigations. Conventional karyotyping and cell culture are also available when required. N.B. Full mutation screening of gene panels by next-generation sequencing is not currently available in a prenatal context.
Information for patients
Patient information guide on prenatal array-CGH
Information for healthcare professionals
Prenatal service guide.
Recommendations for the use of chromosome microarray in pregnancy published by the Joint Committee on Genomics in Medicine (JCGM) which includes a sample consent form.
Mr Mark Bateman
Tel: 01772 429085
Principal testing approaches:
Quantitative Fluorescence-PCR (QF-PCR)
QF-PCR is provided for the rapid detection of the common viable trisomies (trisomy 21, trisomy 13, trisomy 18), triploidy, and gains and losses of the sex chromosomes.
All NHS prenatal referrals are provided with this test.
This test alone is undertaken for screen-positive or Non-Invasive Prenatal Testing (NIPT) confirmation referrals.
The majority of results are available within 3 working days (often within 24 hours).
Array Comparative Genomic Hybridisation (Array-CGH)
Array-CGH detects imbalances throughout the genome to a higher resolution than conventional cytogenetic analysis. See Array-CGH page for more information.
This test is available for NHS referrals that have abnormalities detected on ultrasound scan or a nuchal translucency >=3.5 mm.
The majority of results are available in 7-14 days.
This is no longer a routine test, but is available when required (e.g. for familial cytogenetic rearrangements, or the investigation of low-level cytogenetic mosaicism).
The majority of results are available in 10-14 days.
Viable cells can be propagated in culture to facilitate biochemical assays or for long-term storage.
Molecular genetic analysis
DNA can be extracted from prenatal samples to enable the diagnosis of a wide range of single-gene disorders.
For such tests, the laboratory needs to be notified in advance to ensure that appropriate preparatory investigations have been performed and that the sample will be adequate for the test.