An experimental gene therapy developed by researchers at UCLA, University College London and Great Ormond Street Hospital has restored and maintained immune system function in 59 of 62 children born with ADA-SCID, a rare and deadly genetic immune disorder.

Severe combined immunodeficiency due to adenosine deaminase deficiency, or ADA-SCID, is caused by mutations in the ADA gene, which creates an enzyme essential for immune function. For children with the condition, day-to-day activities like going to school or playing with friends can lead to dangerous, life-threatening infections. If untreated, ADA-SCID can be fatal within the first two years of life.

The current standard treatments— bone marrow transplant from a matched donor or weekly enzyme injections—come with limitations and potential long-term risks.