By Dr Ananya Mandal, MD
Gene therapy can offer a cure for a rare condition that causes children’s immune systems to fail. In this rare condition, known as Severe Combined Immunodeficiency (SCID), inherited genetic mutations mean that babies are unable to fight off infection, severely limiting their chances of surviving more than a few years. Severe combined immunodeficiency (SCID) is a rare genetic disorder estimated to affect between 1 in 200,000 and 1 in 1,000,000 live births
In a new study researchers have shown the results of a trial that found that gene therapy was successful in 14 out of the 16 UK children they treated, allowing them to recover to lead normal lives. The technique works by introducing a working copy of the mutant gene, which provides the body with instructions on how to produce working immune system cells. The child followed for the longest time, nine years, still had functioning immune cells, showing that gene therapy works in the long-term.
Prior to gene therapy the only other option for children with the most common form of SCID was to receive a bone marrow transplant, which relied on finding a suitable match. This new technique, while not without risk, offers a credible treatment option in cases where a suitable donor cannot be found.
Doctors and researchers from the Institute of Child Health and Great Ormond Street hospital yesterday published research papers describing the long-term outcomes of gene therapy for children born with SCID. Their two papers, published in the journal Science Translational Medicine, describe positive long-term outcomes for the majority of the children they treated with gene therapy, who have been able to lead relatively normal lives since receiving treatment.
In the two longer-term follow-up studies recently published in Science Translational Medicine, the underlying genetic defect was repaired in four out of six patients with Adenosine Demaninase-Deficient SCID, and 10 out of 10 patients with X-linked SCID. Immune cell production was restored, and the effects persisted up to nine years after therapy (the most recent point of measurement). The procedure produced minimal side effects, and patients could attend typical schools.