Spinal Muscular Atrophy (SMA) is a severe genetic disease that causes weakness and muscle loss due to a mutation in the SMN1 gene. This disease is characterised by degeneration of the lower motor neurons, resulting in muscle weakness and atrophy. Its occurrence in newborns makes it the most prevalent genetic cause of infant mortality.

Currently available treatments, such as certain drugs or viral therapies, have helped to improve motor skills and increase the survival rate of SMA patients, but it has not been possible to find a therapy that is long-lasting. A clinical trial with the drug Zolgensma was approved in 2019, after which it was approved for use by the FDA. Three years later, in January 2022, there were no specific data to indicate that patients treated with Zolgensma were still alive. The price of the drug set by the manufacturer in the US was around $2.1 million per treatment.

The results of the study that has been published in the journal Nature Communications show how the team of researchers led by Dr. Izpisua has used the gene editing technology called CRISPR-Cas9, combined with a method known as HITI previously developed in a project promoted and funded by UCAM, to silence the defective SMN1 gene and insert a correct copy of the gene in mice with SMA. ‘By silencing the defective gene and adding a healthy version of it, we observed significant and lasting improvements in the health and motor function of mice with SMA,’ says Estrella Núñez, Vice-Rector of Research at UCAM and a collaborator in the study.

The data obtained showed an increased survival rate of mice treated with this method compared to conventional therapy, especially in the case of males, where survival was increased by more than 150%. The median survival of male mice treated with this novel treatment was 182 days, compared to 72.5 days for conventional treatment. For females, median survival was 220 days, compared to 176 days for conventional treatment, an increase of 25%.

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