Researchers at Oregon Health and Science University say they’ve developed a new — and safe — form of genetic therapy.
Using monkeys, they say they’ve figured out how to get rid of genes that cause disorders like diabetes and heart disease — without the worry of side effects.
As Kristian Foden-Vencil reports, their hope is that in a few years, the new therapy will be used in humans to prevent diseases before a child is even born.
Many medical disorders run in families: Generation after generation can be plagued with heart disease; a certain form of cancer; or neurological problems.
Up to now, such families have pinned their hopes on therapies that try to cut the offending genes out of a strand of DNA — and then replace it with a healthy section.
But that process is extremely exacting and difficult. Researchers say trials in animal have resulted in many abnormalities.
But researchers at OHSU’s primate center say they’ve come up with a new and much simpler system.
Shoukhrat Mitalipov: “You know, in terms of technical difficulties. It’s not very complicated and I believe every clinical setting can perform these procedures.”
Shoukhrat Mitalipov is the lead scientist for this research at OHSU's Primate Center in Beaverton. In this month’s on-line edition of the journal ‘Nature,’ he outlines how his team produced four seemingly healthy monkeys using the eggs of two females and the sperm of one male.
Shoukhrat Mitalipov: “We were surprised that we didn’t have any adverse effect in termsof embryo development. We didn’t have any abnormalities and all offspringwere healthy.”
Instead of cutting up strands of DNA, Mitalipov focused on how some types of DNA are located in different areas of a cell– and therefore can be separated easily.
Stick with me here, things are going to get a little complicated. But think of a cell as a chicken egg.
The yoke is the nucleus and the white is the cytoplasm. Ninety-nine percent of the DNA is stored and protected within the yoke. But a small amount of mitochondrial DNA floats around the white or cytoplasm.
Mitochondrial DNA is used to build the power houses that keep a cell alive. It's also only passed on by the mother. And if it contains mutations, they cause diseases like diabetes, some forms of cancer, neurological problems and even infertility.
What Mitalipov’s team has done is basical take the nucleus from the egg cell of one female monkey – with 99 percent of its DNA –and matched it with the cytoplasm of another healthy female, effectively ending up with an egg without any mutated mitochondrial DNA.
Shoukhrat Mitalipov: “We believe that this technique can be applied to existing human IVF techniques where a woman that carries this mutations can now have her own biological child, but her mitochondrial DNA causing these diseases can be replaced with healthy mitochondria.”
About one in 200 children suffer from some mutation of their mitochondrial DNA.
The therapy’s earliest use might be for a couple who’ve already had one child with a disease.
They’d use it to make sure their second child didn’t suffer from a similar problem.
The therapy raises many ethical and legal issues, particularly with regard to a child having two mothers and one father.
Before moving into clinical trials, Mitalipov’s team will have to convince the federal government that it’s both safe and desirable to make genetic alterations that will continue for generations to come.