Tuesday, 3 February 2015

Three-person parentage: IVF treatment vote in UK

MPs in the UK House of Commons have voted 'Yes' on allowing IVF treatment which would see the first children born with three genetic parents. 

Original article
The UK's House of Commons is to vote on a law allowing revolutionary in-vitro fertilisation (IVF) treatment which uses genetic material from a third parent. The treatment is designed to allow couples whose children would suffer from mitochondrial diseases.

[caption id="attachment_248" align="alignright" width="300"]Mighty mitochondria! Cutaway diagram of a mitochondrion showing the two membranes and cristae (folds). Image credit: Blausen.com. [/caption]

As every biology student knows, mitochondria are the power-houses of the cell. There are many mitochondria in each cell which generate much of the cell's energy needs. They also have their own DNA (mtDNA) which can result in disease if enough of it becomes damaged.

The mtDNA is unique. Unlike the DNA in our nuclei, half of which comes from each parent, mtDNA comes only from our mother. This is because mitochondria are inherited through the egg cell - sperm don't carry them. This also means mitochondrial diseases like diabetes mellitus and deafness, and myoclonic epilepsy with ragged red fibres are passed on through the female line.

The procedure

The IVF treatment before the House of Commons involves a donor mother giving up an egg cell. The nucleus of the cell is removed, leaving only her healthy mtDNA in the cell. The mother's DNA nucleus is then transplanted from her egg into the healthy donor egg. This new egg, a combination of the mother's DNA and donor's mtDNA, is then fertilised in-vitro by the father's sperm.

There is no risk of the original mother's mtDNA disease being passed on to her child, and the donor's mtDNA only accounts for a tiny percentage of the overall DNA. The transfer of mtDNA should also have no bearing on the appearance of the child, as mtDNA encodes genes related for the production of energy within the cell. This means that the child is still ~99% the offspring of the original parents, with the donor accounting for the rest. Nevertheless, the child is the product of three biological parents.


Despite this treatment being of use to many potential parents - according to a BBC article some 150 couples could make use of this and some have even gone through the torture of losing children to mitochondrial disease - there is still much opposition to the idea of three biological parents.

Both the Catholic and Anglican churches have come out against the procedure, as well as self-styled genetics watchdog Human Genetics Alert, questioning the ethics of the procedure and the precedent it sets for modifying human genes.

Safety concerns have also been voiced by other scientists, however the Nuffield Council on Bioethics and the Human Fertilisation and Embryology Authority in the UK have ruled it an ethical and safe procedure.

It's the opinion of this scientist that, if shown to be a safe procedure, the transfer of mitochondria is no different than having an organ transplant from a non-parent in terms of ethics.

If replacing the batteries grants a full life where otherwise a tragically truncated one would exist then, by all means, break out the Duracell.

1 comment:

  1. […] a female donor. The treatment should help 150 couples a year conceive healthy children. Read more here and on the […]