Cure for cystic fibrosis nears as scientists fix genetic mutation

A CURE for cystic fibrosis is on the horizon after scientists corrected the genetic mutation which causes the condition in human cells.

Around one in 2,500 babies is born with the condition, which causes a build-up of thick, sticky mucus in the body, blocking the lungs and digestive organs.

The condition is caused by a faulty piece of DNA which fails to produce enough water to dilute the mucus.

Now scientists from the Hubrecht Institute in the Netherlands have shown that a healthy piece of DNA can be swapped for the defective code, allowing cells to function normally.

In mini intestinal organs grown from human stem cells – known as organoids – the team showed that inserting the new DNA into the malfunctioning tissue caused the cells to plump up with extra fluid.

“The treated organoids demonstrated the same response as the healthy organoids: they became swollen,” Dr Maarten Geurts, the first author on the study, said. “That provided us with proof that our technique worked and replaced the mutated DNA.

“We have for the first time demonstrated that this technique really works and can be safely applied in human stem cells to correct cystic fibrosis.”

Cystic fibrosis is one of the most prevalent genetic diseases worldwide and patients must take a range of medications and undergo regular airway-clearing treatments and exercises. Around 10,600 people in the UK suffer from the condition.

According to the Cystic Fibrosis Trust, one person in 25 carries the faulty gene, usually without knowing, meaning two million people in Britain have the mutation.

If two carriers have a child, it has a one-in-four chance of developing the condition, which can bring symptoms including persistent cough, wheezing, breathing difficulties, repeated chest infections and lower life expectancy.

For the new research, the team used a technique called prime editing, which is a variation of the genetic snipping tool Crispr. The new technique inserts genetic material without inadvertently causing damage elsewhere, and so is less likely to bring unexpected problems. The technique was tested on miniorgans grown from stem cells of patients with cystic fibrosis and compared with those grown from healthy cell lines.

The mutations that cause cystic fibrosis are found in a channel known as CFTR (cystic fibrosis transmembrane conductance regulator) which is present in the cells of various organs including the lungs. Due to the mutations, the channel does not function properly, leaving the layer of mucus that covers the cells with too little water, meaning the mucus becomes sticky.

The technique needs to be adapted for safe use in humans, but researchers said it was a “big step forward”.

The study was published in Life Science Alliance.