PGD (Preimplantation Genetic Diagnosis)
Pre-implantation genetic diagnosis (‘PGD’) was developed in the early 1990s. PGD is a method by which would-be parents may be enabled to have a child who will be free from genetically transmitted conditions, where they are at risk of a heritable condition.
CRGH was an early pioneer in the UK, initially in collaboration with University College London (UCL). CRGH has had many national firsts including the first baby born free from the following inherited cancer predispositions: eye cancer (Retinoblastoma), bowel cancer (Familial Adenomatous Polyposis Coli) and breast cancer (BRCA1).
Who is it for?
Today, CRGH uses PGD widely to prevent the passing on abnormal changes in genes.
Some common indications include:
- Sickle cell disease
- Cystic fibrosis
- Inheritable cancer pre-dispositions
- Huntingdon’s Disease
- Muscular dystrophies
Another common indication for PGD is rearrangements in chromosomes. However, we also offer PGD to avoid rare conditions such as Harlequin Icthyosis. If the condition has not previously been undertaken with PGD in the UK, we are willing to apply to our regulator, the Human Fertilisation and Embryology Authority (HFEA) to seek permission to treat.
How it works
PGD involves taking eggs and sperm from the intending parents (or sometimes from a donor) and achieving fertilisation in the laboratory (Please see our IVF/ICSI web page). The resulting embryos are allowed to develop for five to six days. These embryos are termed as blastocysts. A small number of cells is taken from the embryos (biopsy). They are tested for the specific genetic conditions or chromosomal rearrangement, using the test which has been specifically prepared for each couple. The embryos are frozen. One (or sometimes two) suitable embryo(s) may be transferred to the womb. If the PGD treatment is successful, the pregnancy may proceed with normal antenatal care.
Prospective parents should seek referral to the CRGH from a geneticist in their local area. Regional genetic services cover all areas in the UK. We are able to advise private patients including those from overseas regarding private genetic counselling. This person will see the parents to take an initial history and will you advise on the appropriateness of PGD. The geneticist may then make a formal referral to CRGH (the tertiary care provider). We will arrange a first visit within one to two weeks of receiving a referral letter.
What to expect?
You will be seen by a geneticist for a PGD consultation. A fertility assessment check will be carried out and necessary laboratory PGD work up will be prepared. You will then be seen by a Consultant Gynaecologist and an IVF nurse to discuss your treatment. Your PGD treatment will start once the
laboratory work up is ready.
We treat both NHS and private patients. We have an NHS England PGD contract. Presently, NHS funding is immediately available if couples meet the national criteria set by the NHS.( NHS criteria doc ) Individual funding applications are not required for PGD treatment.
Social sex selection
We are from time to time asked to provide information which would allow parents to select the gender of their prospective child. We do not provide such information since sex selection is illegal in the UK.
PGD Success Rates at CRGH
Since 1996, the Centre for Reproductive and Genetic Health (CRGH) has offered patients a full range of highly specialist PGD services, and achieved many national firsts in the field. These include the first baby conceived free of the breast cancer gene, the first baby born free of retinoblastoma (a form of eye cancer) and the first centre to test for Familial Adenomatous Polyposis (FAP) which can lead to early onset colon cancer. CRGH was the first unit in Europe to achieve a live birth using Karyomapping.