The European Society of Human Reproduction and Embryology (ESHRE) has published an updated set of best practice guidelines for fertility clinics on the use of  preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS) techniques.

The new guidelines are separated into four documents intended 'as a set which…form a complete best-practice compendium', said Dr Gary Harton, the ESHRE PGD Consortium chair and Head of Molecular Genetics at Reprogenetics in New Jersey. The first document offers guidance on the organisation of a PGD centre, including criteria for selecting patients, the provision of counselling and accreditation.

The other three relate to PGD/PGS methods: DNA amplification-based testing,fluorescent in situ hybridisation (FISH)-based testing and biopsy/embryology. The fourth guideline updates when and how embryos and polar bodies - chromosomes discarded byeggs during fertilisation that can be screened for maternal chromosomal abnormalities - should be biopsied and stored.

Previous guidance issued in 2005 suggested PGD, which commonly involves the removal and testing of one or two cells from an eight-cell blastomere, is technically more demanding than other routine genetic tests and requires specific guidance.

The Consortium included PGS in its guidance to 'develop the best laboratory and clinical practice possible', said a press release, despite evidence suggesting the technique is ineffective using current technology at embryo cleavage stage. Future trials may show PGS to be more effective, if used at the blastocyst stage or on polar bodies.

In 2005, the Consortium devised comprehensive guidelines because there was no scientific consensus on the clinical and technical aspects of PGD and many countries lacked regulation. The Consortium decided to revise its guidelines because of rapid developments in PGD application and techniques since 2005 and greater availability to patients.

All four papers were published online in the journal Human Reproduction on 21 October 2010. 

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.