HFEA confirms that HLA tissue typing may only take place when preimplantation genetic diagnosis is required to avoid a serious genetic disorder

Date issued: 1 August 2002

The HFEA  confirmed today that tissue typing through preimplantation genetic diagnosis (PGD) may only take place when PGD is required to select embryos for treatment that are not affected by a serious genetic disorder. (1)

An HFEA Licence Committee decided it could not agree to a request from a clinic to use Human Leukocyte Antigen (HLA) tissue typing solely to select an embryo so that stem cells from the resulting baby's blood could be used to treat an existing sibling affected by Diamond-Blackfan Anaemia (DBA). (2)

Although some children with DBA inherit this genetic condition from carrier parents, most cases arise as a result of a sporadic mutation. In such cases, where neither parent can be demonstrated to be a carrier, the risks of having a further affected child are considered relatively low. PGD would only be applicable when parents were carriers and where the mutation could be tested in the embryos.

The HFEA Licence Committee was informed that, in this particular case, neither parent appeared to be a carrier of the genetic mutation, the existing child's condition was likely to be a sporadic case, and that embryos conceived in the future by these parents would not be at significantly greater risk of DBA than embryos conceived by the general population. Therefore it could not be argued that PGD was necessary to select embryos free from the condition.

In November 2001, the HFEA agreed on conditions in which PGD/tissue typing would be consistent with the terms of the Human Fertilisation and Embryology Act (1990) and the results of a public consultation on the acceptability of PGD. (3)

One of the criteria is that:

'the embryos conceived in the course of this treatment should themselves be at risk from the condition by which the existing child is affected'

Dr Maureen Dalziel, HFEA chief executive, said:

'Diamond-Blackfan Anaemia is an extremely serious condition and we have enormous sympathy for the affected child and his parents. However, the Authority is unable to approve this application for PGD/tissue typing because it does not meet the carefully considered criteria laid down to ensure that the procedure is lawful and ethical'.

Ends.

Notes to editors

• PGD involves the removal of a cell from an embryo created by in vitro fertilisation. The cell is then tested to see if the embryo carries a genetic disorder. This is usually three days after fertilisation when the embryo has six to ten cells. Human Leukocyte Antigen (HLA) tissue typing is an additional step to determine the tissue-compatibility of embryos free from the disorder with an existing sibling.
• DBA is a rare disorder with an incidence of 5-7 per million live births. In the majority of cases the DBA is sporadic. In 20-30% of cases there is a positive family history with anaemia of varying severity.
• The HFE Act Schedule 1(1)(d) permits a Licence Committee of the HFEA to grant a licence authorising:

'Practices designed to secure that embryos are in a suitable condition to be placed in a woman or to determine whether embryos are suitable for that purpose.'

The HFEA agreed at its meeting on 29th November 2001 that, in principle, PGD with HLA typing may be permitted subject to the following criteria:

• the condition of the affected child should be severe or life threatening, of a sufficient seriousness to justify the use of PGD;
• the embryos conceived in the course of this treatment should themselves be at risk from the condition by which the existing child is affected;
• all other possibilities of treatment and sources of tissue for the affected child should have been explored;
• the techniques should not be available where the intended recipient is a parent;
• the intention should be to take only cord blood for purposes of the treatment, and not other tissues or organs;
• appropriate implications counselling should be a requirement for couples undergoing this type of treatment;
• families should be encouraged to participate in follow-up studies and, as with PGD, clinics should provide detailed information about treatment cycles and their outcomes;
• embryos should not be genetically modified to provide a tissue match.

The HFEA assess applications for PGD with tissue typing on a case by case basis.