Gene editing technique can treat thalassemia in womb

New York, July 11: In a breakthrough, a gene editing technique has shown potential to treat beta thalassemia -- a genetic blood disorder -- paving the way for treating various genetic conditions during early stages of foetal development.

The blood disorder condition reduces the production of haemoglobin -- a protein in red blood cells that carries oxygen throughout the body.

Researchers from the Carnegie Mellon University in the US used a peptide nucleic acid (PNA)-based gene editing technique to successfully treat beta thalassemia in adult mice.

PNAs are synthetic molecules that combine a synthetic protein backbone with the nucleobases found in DNA and RNA.

Mice treated using PNA while in utero showed levels of haemoglobin that were within the normal range, less spleen enlargement and increased survival rates, the researchers said.

"Early in embryonic development, there are a lot of stem cells dividing at a rapid pace. If we can go in and correct a genetic mutation early on, we could dramatically reduce the impact the mutation has on foetal development or even cure the condition," said Danith Ly, Professor from the varsity.

In the study, published in the journal Nature Communications, the team showed that just one injection of the PNA complex into the amniotic fluid during gestation led to dramatic improvements in the mice's symptoms and correction in 6 per cent of the beta thalassemia causing mutations.

The technique showed no off-target effects from the treatment, suggesting that the method would be better than other gene editing techniques like CRISPR/Cas9, which can erroneously damage off-target DNA.

"The PNA technique is more ideal for therapeutics. It doesn't cut the DNA, it just binds to it and repairs things that seem unusual. We looked at 50 million samples and couldn't find one off-site error when we used our PNA gene editing technique," Ly noted.

According to the World Health Organisation, nearly 1.1 per cent of couples worldwide are at risk for having children with a haemoglobin disorder and 2.7 per 1,000 conceptions are affected.

India has the largest number of patients with thalassemia major in the world -- about 1 to 1.5 lakh -- and about four per cent of the population are carriers of the beta thalassemia trait.

The technique might be able to achieve even higher success rates if they can administer it multiple times during gestation, the researchers said.