30 June 2013

UK to Draft IVF Regulations for Use of Third-Party Mitochondria

On Friday, the BBC reported that the UK government will be developing regulations allowing for the use of third-party mitochondrial DNA in an in vitro fertilization procedure. This is pretty cool; let me explain what that mouthful means.

In vitro fertilization is a major and often last ditch treatment when a woman cannot have a baby. In this treatment, an egg is removed from a woman and fertilized with sperm outside her body, under very carefully controlled conditions. The fertilized egg is then implanted into a woman's uterus, in the hopes that the fertilized egg will develop normally and a healthy baby will be born. This technique is often used when a mother has blocked fallopian tubes, pelvic adhesions or endometriosis or when a father has a low sperm count or sperm with low motility.

Since we're talking about fertilizing an egg without the necessity of sex, this process offers some  nifty possibilities. A lesbian couple can use an egg from one of them with donated sperm to have a baby; a gay couple can use their sperm to fertilize an egg that will be carried to term by a surrogate mother, or a straight couple can use either or both of their eggs and sperm and enlist the help of a surrogate.

The proposed UK regulations would take things one step further and replace the mitochondria from the egg with the mitochondria from another woman. You may remember from your biology class in high school that mitochondria are tiny organelles found inside most of the cells in living things like animals and plants. Mitochondria produce the energy that cells need to live and do the things the cell is meant to do. Without properly functioning mitochondria, the cell will waste and die.

In humans, mitochondria are found inside every cell except for red blood cells, and malfunctioning mitochondria can cause neuromuscular disorders that may result in blindness, heart disease and death. The really neat thing about mitochondria is that they have their own DNA, and the mitochondrial DNA always comes from the egg. In other words, all of the mitochondria in your body have their own genetic code, which is different from your chromosomes, the genetic code which you will pass on to your children, and comes exclusively from your mother.

The IVF technique approved by the British government would take the key parts of the mother's egg, before or after fertilization, and swap them into the egg from a third-party donor with healthy mitochondria before implantation into the body of the woman who will carry the child to term. The child conceived from this method would carry the chromosomes of the mother and the father, and the mitochondria of someone else. This is pretty cool, because all of the important DNA that makes you you comes from the chromosomes of your parents; the DNA of your mitochondria doesn't matter.

Here are two helpful graphics produced by the BBC from its report. In the process illustrated below, the key parts of a fertilized egg are implanted into the fertilized egg from a donor:

BBC News
In this next process, which strikes me as simpler, the key parts of an unfertilized egg are implanted into an egg from a donor.

BBC News
This process won't be available in Canada until it has been approved as a funded procedure under the various provincial health insurance programs. You might want to keep an eye on the website of Health Canada; the Assisted Human Reproduction Agency of Canada was shut down by the federal government on 1 October 2012.

4 comments:

  1. I always found JP's website and blog very helpful however I must say you missed the mark a bit on this post.

    The first sentence of the second paragraph speaks to IVF being "a major and often last ditch treatment when a woman cannot have a baby". Though I'm sure it was not intentional, I found it very disappointing that you would sum up the need for IFV because "a woman cannot have a baby". As someone who experienced (side by side with my husband) the struggle to get pregnant and the overwhelming joy and blessing of a successful IVF treatment, I find it insensitive that you would sum up the need for IVF because of the failure of a woman to have a baby.

    Last time I checked it takes more than a uterus to make a baby :-).

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    1. Thanks very much for your input. Comments like this are invariably helpful.

      To explain myself, I did consider how I would frame the basic purpose of IVF, before getting into more details such as it's specific use when "a father has a low sperm count or sperm with low motility," which appears at the end of the same paragraph. Bearing in mind that I try to make this blog as plain language as possible, I thought it would be easier to say "when a woman cannot have a baby," which is essentially accurate, than to say "when a woman is unable to conceive or carry a baby to term for number of reasons including..." and so on.

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    2. I think your use of plain language is one of the many reasons your website and blog is such a useful resource. And in keeping with this, it could have simply stated "IVF is an increasingly popular option for couples who are struggling to make a baby". This plain statement would have covered same-sex couples, making it inclusive, easily understood and eliminating the inference that when fertility issues exist it is due to a problem with a woman's body. If I may stress, I believe a great deal of thought and consideration goes into all the information posted on the blog and I have no doubt there was no intention to convey anything other than helpful information.

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    3. That's a fine point too, except that it's not always a couple that pursues IVF, and I didn't want to imply that that was the case. A single woman might pursue this with donor sperm. I think I covered the perception that fertility issues solely concern women's bodies when I discuss the problems with low sperm counts and sperm motility. Thanks very much for your comments, they are appreciated.

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