Scientists create three-parent embryos

[Cynaburst]

LONDON (Reuters) - British scientists have created human embryos with three parents in a development they hope could lead to effective treatments for a range of serious hereditary diseases within five years.

Researchers from Newcastle University, in northern England, presented their findings at a medical conference at the weekend, a university spokeswoman said on Tuesday.

The IVF, or test-tube, embryos were created using DNA from one man and two women.

The idea is to prevent women with faults in their mitochondrial DNA passing diseases on to their children. Around one in 5,000 children suffer from mitochondrial diseases, which can include fatal liver, heart and brain disorders, deafness, muscular problems and forms of epilepsy.

If all goes well, researchers believe they may be able to start offering the technique as a treatment in three to five years.

Mitochondria are tiny power packs inside cells that provide their energy. Faulty genetics can mean mitochondria do not completely burn food and oxygen, leading to the build-up of poisons responsible for more than 40 different diseases.

The Newcastle team believe these diseases could be avoided if embryos at risk were given an effective mitochondrial transplant. The process involves in vitro fertilization (IVF) and the subsequent removal of the egg's nucleus. The nucleus is then placed into a donor egg whose DNA has been removed.

The resulting fetus inherits nuclear DNA, or genes, from both parents but mitochondrial DNA from a third party.

"The idea is simply to swap the bad diseased mitochondria -- give a transplant, if you like -- for good healthy ones from a donor," Patrick Chinnery, a member of the Newcastle team, said in a telephone interview.

"We're trying to prevent kids being born with fatal diseases." Mitochondrial DNA is passed down only through the female line.

The technique has so far been tried only in the laboratory, using abnormal embryos left over from IVF therapy, and the handful of three-parent embryos created were destroyed after six days.

Stiff opposition to the technique is likely from critics of embryo research who fear the creation of designer babies.

The research was presented to the Medical Research Council Centre for Neuromuscular Diseases conference in London on February 1-2.

(Editing by Robert Woodward)



MODERATOR'S EDITORIAL NOTE:

I just happened to read this article on the internet today. I don't think that this method can be applied to HCM, at least not as it is, since the mitochondrial DNA are a different thing that the DNA mutations which cause HCM, but it sure is interesting research. I would love to hear the take of our new moderator Gordon.

[gfox42]

Good question: is this likely to eventually turn into something useful for those with HCM? It's certainly possible, but not in the immediate future.

Most of our cells contain two different sets of genes, called "genomes" in scientific jargon: the genes in the cell nucleus and the genes in the mitochondria. There are many more genes in the nucleus. The mitochondria are crucial, though. They're sometimes called things like "the powerhouse of the cell" in the popular press, because the basic storage of chemical energy from food occurs in mitochondria.

The genes known to contribute to HCM occur in cell nuclei, not mitochondria. Many of these genes code for parts of the heart muscle (called sarcomeres) that are essential for muscle contraction.

There are two reasons to think it's possible that there's a mitochondrial connection for HCM. First, the known mutations only account for something like 60% of HCM cases. That suggests that there may be entirely different types of mutations that also cause HCM. Second, there's some evidence that problems in energy function can lead to HCM. If you search Google for "mitochondria HCM" you'll get quite a lot of hits -- not exactly scientific evidence, but it's clear that there's a fair amount of research on this.

If you can stand a bit of scientific jargon, take a look at the review at http://www.medscape.com/viewarticle/553426_3 (and particularly their Figure 1). The basic idea here is that in addition to problems with inefficient sarcomeres, problems with energy use can lead to HCM. I can't say anything about how strong the evidence is for this viewpoint -- I'm already pretty far out on a limb -- but it's certainly a reasonable hypothesis for researchers to study.

Remember how you learned that you get one copy of each gene from each parent? This isn't true for mitochondrial genes: you get all of them from your mother. The reason is this: your father contributes half the nuclear DNA, but your mom contributes half the nuclear DNA plus the entire egg cell -- which is where the mitochondria come from. So if mutations in mitochondrial DNA contribute to HCM, those particular mutations come from your mother (and grandmother, etc.) only. Among other things, that means that researchers would use different methods to look for mitochondrial genes in family trees than they'd use to look for nuclear genes.

So why do I say "not in the immediate future?" First, we don't yet know that there are many mitochondrial genes that contribute to HCM -- not all reasonable hypotheses turn out to be true! Second, the next step -- being able to use this kind of technology as part of in vitro fertilization -- might turn out to be difficult.

Gordon

[Pam Alexson]

Sometimes this computer stuff is a pain when we try to view an article. Gordon it requires one to register to get the article and some members have trouble with that and such... yes I do too.
What I did for instant gratification was, while logged on here and looking at this thread , I googled, "inefficient sarcomeres, energy problems in HCM."

That allows you to pick it write off the hit list of different readings about this topic.
Some of us are still way behind in computer savy and I am one of them. Thanks for the article ..it is great!

Here is one clinical article to support what you say, that will go through without registration requirement. Pam

http://content.onlinejacc.org/cgi/content/full/41/10/1776

[gfox42]

Doh! I sometimes forget . . . I'm using the university's connections and all of its licenses . . . so sometimes have access to things they've paid for. I'll try to avoid doing that in the future.

Gordon