New Hope for Families With Genetic Risk

A new method for screening embryos is helping people at risk of having children with inherited disease make informed choices

Editors' note: This is the second of two perspectives on preimplantation genetic haplotyping, a procedure for screening embryos for inherited disease (see, 7/20/06, "Confessions of a 'Genetic Outlaw'").

Developments in medicine, particularly those resulting from a better understanding of molecular biology and genetics, mean that given the appropriate information, families and individuals can make informed choices on how best to manage medical conditions. For some, this can mean making reproductive choices. Preimplantation genetic haplotyping, a new procedure for screening embryos for inherited disease, is one such development.

Critics say advancements such as this one can foster the creation of "designer babies." As chief executive of the U.K.'s Cystic Fibrosis Trust, I robustly challenge such accusations and defend families' rights to make informed decisions.


 An understanding of the challenges facing people with cystic fibrosis (CF) and their families helps explain why. Having a child diagnosed with CF is a shock for most families. CF is a life-threatening condition whereby vital organs, particularly the lungs and the organs of the digestive system, become clogged with thick, sticky mucus. It is a very complex disease that makes heavy demands on the families and individuals affected.

Most settle into a new pattern of life that involves considerably more than the normal adaptations following a baby's birth. All babies seem to need a huge amount of paraphernalia, making every outing complicated. But the daily routine is far more demanding for a child with CF. Oral, nebulized, and sometimes intravenous medication has to be administered; physiotherapy has to be learned and practiced.

Regular outpatient visits to CF specialists are vital, and occasional inpatient stays may be necessary. If CF is diagnosed at birth and treated appropriately, which in clinical terms tends to mean aggressively, the affected child usually stays well. Good health is maintained by adherence to an onerous daily routine and paying almost obsessive attention to detail.


 It was recently estimated by a CF mother that if all the treatment recommended for a year for her typical CF child was concentrated into a continuous period of time, it would take from Jan. 1 to Mar. 9 to complete, working 12-hour days with no breaks.

Some families cope better than others, and a minority don't cope well at all. Children and teenagers often rebel, and compliance with treatments becomes an issue. All this is set against a backdrop of fear and hope. The fear is that symptoms will worsen, health will deteriorate, and that eventually staying alive with a reasonable quality of life will become impossible. The hope is that a cure or at least a dramatic improvement in treatment will come in time.

CF is a genetic condition that occurs when both parents are carriers of the CF gene. Though healthy themselves, a set of parents that carries this gene have a one-in-four chance of passing on the condition to each child they have. Once one child has been diagnosed with CF, there is a significant risk that subsequent children may also have CF. So families are faced with serious decisions about future pregnancies, as are other families known to be at risk of having a child with a serious genetic disorder.


 In the past, families affected by CF had limited choices. They could decide not to have more children or to take a chance and hope that subsequent offspring did not have this life-threatening condition. In the 1980s the option of antenatal diagnosis became a reality. So parents who decided to go down this route could conceive a child, have an antenatal test at between 10 and 15 weeks of pregnancy and consider whether to have the pregnancy terminated if the baby had CF.

This development was welcomed by many families. Some who had deferred having more children embarked on a pregnancy in the knowledge they had the option to terminate. However, this situation is far from ideal.

To abort a much longed-for child is not a decision that anyone takes lightly, and to reconcile this decision with the love and commitment they may already have for a child with CF makes the emotional turmoil even more complex. Some families could not contemplate termination, so either had no more children or took their chances.


 Of course, there were those who opposed termination even for such serious health reasons, and they made their views known in vociferous debate. The Cystic Fibrosis Trust never advocates a particular choice. We try to ensure that families are given complete and correct information and are supported in whatever choice is right for them.

More recently, the option of pre-implantation genetic diagnosis increased families' options. The procedure involves the creation of embryos as if for in-vitro fertilization, but rather than being a method to overcome infertility, it offers more palatable choices to those at risk of having a child with a life-threatening disease.

It is not easy, because three or four cycles are sometimes necessary to achieve a pregnancy, and at several thousand dollars a go, many cannot afford it. The procedure itself is quite stressful and not without risk, so it is not an option to be taken lightly.


 However, for those who do not want to bring another child with CF into the world and for whom a termination is unacceptable, pre-implantation diagnosis offers a positive way forward. Until recently it was only technically possible for those who carried the most common CF mutation (more than 1,200 mutations have been identified to date) and some couples could not take advantage of it.

This new technique has changed all that. By identifying a CF-affected gene without having to identify the specific mutation, all couples who know they are at risk of having a child with CF can consider pre-implantation diagnosis.

Again, there have been hostile voices, accusations of "playing God" or creating "designer babies." However, we are not trying to create exceptionally beautiful children, very talented children, or any sort of "super" baby. We are simply trying to ensure that this child makes healthy mucus like most of the rest of us and doesn't have to face a life of constant treatment, clogged airways, and a shortened life expectancy.

Alleviating human misery lies behind a lot of medical research. We try to cure the common cold. We develop vaccines. We attempt to second guess and outwit cancer. Are we redesigning human beings or playing God in those cases? As a practical measure to give families who usually already have one child with CF the option of sparing another child the same condition, this development is to be warmly welcomed.

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