Doctors in Calgary have used gene therapy, in what is believed to be a world-first, to treat a patient with a rare condition that can damage major organs.
The man has Fabry disease, which is a rare, inherited enzyme deficiency that is known to effect more than 400 Canadians. It results in a build-up of fat known as Gb3 and can lead to problems with the kidneys, heart and brain.
It occurs when a particular gene, known as the GLA, has had its genetic code altered and doesn’t function as it should.
If left untreated the average lifespan for men is 45 years and 55 years for women.
A medical breakthrough came in January 2017, when doctors inserted a working copy of the gene into the patient’s stem cells and transplanted them back into the patient’s body by means of a specially engineered virus.
“It [the virus] has been modified extensively; it doesn’t cause infection, it doesn’t cause human disease, it just puts the gene for Fabry disease in the cells and then it dies off,” explained Dr. Aneal Khan, a medical geneticist with Alberta Health Services.
Currently, Fabry disease is treated using enzyme replacement therapy, which requires patients be given an injection of proteins every two weeks.
Dr. Khan said Thursday it’s still too early to determine what impact the gene therapy will have. Doctors will monitor the patient for the next five years to see how he reacts to the treatment.
“What we know is that the patient is doing well, but in terms of any improvement as a result of this experiment… we don’t have any data yet.”
If the treatment is a success, Dr. Khan said it could “open the door” to treatment of a number of other metabolic diseases that are also caused by a faulty gene.
“There’s more than 400 metabolic diseases out there. So, overall there are actually quite a few patients that have these rare diseases … and we think the technology, and the platform, could be applied to a number of diseases.” Dr. Khan said.
“In those other diseases one would have to develop a different platform, put in a different gene; but the steps will be the same.”
He said they are currently looking for other patients, but that the trial is only open to men for the time being. That’s because the gene is on the X chromosome and, as a result, enzyme levels can only be measured reliably in males.