Should baby be risked for sister?

By Vivienne Parry
Radio 4’s Inside the Ethics Committee

 

Catherine is a little girl condemned by genetic disease to a gruelling regime of treatment.

She could be released from it by a sibling, but the sibling is not yet conceived.

And can one child’s health ever be put at risk to save another’s?

When Catherine, the first child of Charles and Clara, was born in 2001, she seemed healthy – but not for long.

“She was very listless and would fall asleep in the middle of a feed,” said her mother.

“When she was 11 weeks old, she was pretty much pure white, you couldn’t even see her lips. We took her into A&E.”

Tests revealed that Catherine had virtually no red blood cells.

She was eventually diagnosed with Diamond Blackfan Anaemia (DBA), a genetic disease in which few if any red blood cells are produced by the bone marrow, producing anaemia.

DBA can be treated with day long monthly transfusions.

However, every transfusion adds iron to the body which will cause irreversible organ damage unless removed.

Removal involves giving a drug given as a continuous transfusion through a needle, all through the night, five nights a week.

“Catherine hated it, screaming ‘I don’t want it, I don’t want it’,” said Clara.

“She got used to it, but often said: ‘Why can’t I be normal’.”

Risk of early death

DBA carries a one in four chance of early death because of organ damage and an increased risk of childhood cancer.

“Once we saw what her quality of life was and the problems that she might have in the future, we started saying is there something else we can do?”, said Clara.

A bone marrow transplant was the only option.

One from an unrelated donor carried up to a 30% risk of death for Catherine, one from a related donor a 5% risk.

Charles and Clare had intended having another baby anyway and hoped that a baby brother or sister would be a tissue match.

With each pregnancy there is the same one in four chance of a match.

But it is possible to use a technique normally used in pre-implantation genetic diagnosis (PGD), in which a cell from the three-day-old embryo is taken to screen out serious genetic disease, for tissue typing, to guarantee that a sibling is a tissue match, before being replaced.

The uncertainty of IVF gives a one in 10 chance of successful pregnancy with such a match.

Spontaneous mutation

There was however a major problem: DBA can be inherited or arise as a spontaneous mutation.

Which sort did Catherine have?

 

There was no family history of the condition. Tests on Catherine showed she didn’t have any of the known mutations that cause DBA, but there are some as yet uknown.

It meant that no-one could test whether another baby had the condition or not.

Not being able to rule out DBA was a major ethical issue.

So Clara and Charles decided to have a baby naturally. But the new baby wasn’t a match.

By this time, Catherine was three and the couple were acutely aware that her condition was deteriorating.

She had to have a transplant before she became too sick to survive the procedure.

They decided to go for tissue typing. To do this they needed to have a licence from the Human Fertilisation and Embryology Authority.

But at the time, the HFEA only allowed PGD to be used for tissue typing where a disease could be screened out. This was not possible in Catherine’s case.

So the couple went to the US, where it was permitted. But two attempts failed.

They were psyching themselves up for a third attempt, when they read about a UK couple in the same situation as themselves, who had been given a licence by the HFEA following a judicial review.

They decided to try for a ‘saviour sibling’ using PGD.

Devastating blow

The procedure of taking stem cells for a bone marrow transplant would not harm Catherine’s sibling, because they could be obtained from cord blood at birth.

When baby sister, McKenzie was born, not enough stem cells could be collected for a transplant.

It was a devastating blow – but at least she was free from DBA.

“Every picture I took of them together had added meaning because Catherine was looking at her lifeline,” said Clara.

A much more invasive collection of bone marrow from McKenzie involving 90 minutes of general anaesthesia was now required.

There is no benefit to the donor, and McKenzie was not able to provide consent.

The chances of success for Catherine were getting less as time went on, but the younger McKenzie was, the greater the risks of anaesthesia for her.

Competing interests

Here the ethical issues are the competing ‘best interests’ of the sisters.

There is also the issue that the donation will only cure Catherine’s symptoms, not rid her of the condition.

There is a good chance it could fail. How would McKenzie feel later knowing that her donation failed to save her sister?

And should Catherine’s kidneys fail, then once again, McKenzie would be the first choice of donor.

The Clinical Ethics Committee decided that the bone marrow transplant should go ahead. It took place 18 months ago.

It was a success and Catherine continues to do well.

 

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