gene therapy is showing promise in the treatment of X-Linked Severe Combined Immunodeficiency (X-Linked SCID). Because this is an X-linked disease, males are almost always the ones affected by the condition. People affected by this having recurring infections due to bacteria, viruses, and fungi that naturally occur in the body. In healthy individuals, these do not usually cause any problems, but due to a weakened immune system people with X-Linked SCID can't protect themselves from it.
X-Linked SCID is linked to a mutation in the IL2RG gene. This mutation prevents immune cells from developing and functioning correctly. The new gene therapy involves removing bone marrow from the affected patient and inserting a normal IL2RG gene. Then the bone marrow is inserted back into the patient where it hopefully makes new blood cells and improves immune function.
Three years later, one patient has had continuous improvements in immune function. Another patient died from damage to the lungs before treatment began. This stresses the importance of starting early for the treatment to work. Another 3 patients received treatment 3 to 6 months ago and are now beginning to see improvement.
There have been too few of studies in this to know for sure, but this gene therapy seems to be working so far as long as it is started early. There would need to be more studies done to find out when the optimal time for treatment would be. Hopefully if done early enough, the people affected by this disease could live much longer than usual.