Clinic to screen embryos for cystic fibrosis

Irish Examiner By Eoin English

A leading Irish fertility clinic is to begin screening embryos for cystic fibrosis (CF) to help couples facing difficult family planning choices.

The Waterstone Clinic has been licensed by the Irish Medicines Board to carry out embryo biopsy as part of its new pre-implantation genetic diagnosis (PGD) treatment.

It will be used to identify embryos with Ireland’s most common genetic disease and select ones which are “safe” to transfer as part of the various forms of IVF.

The centre, which carries out roughly 700 cycles of IVF treatment every year, has about six couples under-going IVF poised to avail of the treatment.

It follows the introduction of a new CF alert system in Jul 2011, which sees all newborn babies screened to see if they have CF or are CF carriers.

The centre’s medical director, Dr John Waterstone, said many couples who have learned since then that their baby is a CF carrier now want to know whether one or both of them is a carrier before having another child.

And couples who know they are both carriers — who face a one-in-four chance of having a baby with CF — are forced into making difficult reproductive choices which most never have to face, he said.

“PGD allows science to provide information which can inform these decisions. Some couples are so fearful of the risk of CF that they choose not to have another child. Others avoid the risk by using donor semen — the donor having been screened to ensure he is not a CF carrier.

“PGD is another strategy which ‘at risk’ couples can use in order to have a baby which is genetically their own while reducing the risk of CF to practically zero.

“The process is complex and it is very possible that after all the work, screened embryos may fail to implant so that no pregnancy is produced.

“However, PGD is an option which many at risk Irish couples have chosen over the past decade; now at least some couples who choose PGD will not have the additional burden of having to travel to the UK for treatment.”

The introduction of the service at the Cork centre has been led by Dr Xiao Zhang, head of research and development, in conjunction with laboratory man-ager Dr Tim Dineen.

Scientists there will test embryos three days after fertilisation, removing one cell from each — an embryo biopsy. The remaining cells can still develop normally.
The removed cells will be sent to either Reprogenetics in Oxford or Guy’s and St Thomas’ Hospital in London for genetic diagnosis to identify “safe” embryos which can be selected for transfer during IVF, in the hope that the couples will become pregnant.

All couples will be required to discuss their situation with a genetic counsellor before proceeding with PGD treatment, which can cost up to €10,000 for the first cycle. The technology is applicable to the detection of other genetic risk factors in embryos.

The CFC was established in Jun 2002 by Dr Waterstone, with one nurse, two scientists and a receptionist. Today, the unit on College Rd has a team of over 30.

They achieved the first successful pregnancy in Ireland following embryo vitrification, a new freezing technique, last year, and achieved the first live birth following the technique on Christmas Day.