For those born with three copies of chromosome 21, rather than the usual two, or a total of 23 pairs, gene therapy had been out of the question.
Until now, that is.
While correcting hundreds of genes across the extra chromosome seemed impossible, scientists at the University of Massachusetts Medical School have discovered a way of essentially ‘silencing’ the gene.
A naturally occurring genetic switch, coined the XIST gene, showed it could ‘switch-off’ the entire chromosome at once. Published in the journal Nature, the research might potentially pave the way for treatment of many consequential health problems associated with Down Syndrome.
The world’s leading genetic cause of mental disease, those born with Down Syndrome have an increased risk of heart defects, immune-deficiencies, premature Alzheimer’s and leukaemia.
“Our hope is that for individuals living with Down’s syndrome, this proof of principle opens up multiple exciting new avenues for studying the disorder now, and brings into the realm of consideration research on the concept of ‘chromosome therapy’ in the future,” said Professor Jeanne Lawrence, the study’s lead author.
The breakthrough happened after scientists decided to act on a hunch by inserting the XSIT gene (which are normally associated with sex chromosomes) into the third unwanted chromosome.
After being pleasantly surprised by promising results in lab dishes, the research team have now begun trials on genetically modified mice. Such tests carried out on lab animals are the first step in a long process for testing the safety of a potential new drug for humans.
“I think that the importance of this work is that it now makes it conceivable – not that we know that it will work or that it won’t be a long way off, because there are a lot of questions and a lot of steps to be met,” cautioned Professor Lawrence.
“There are different severities of Down’s syndrome,” she said, adding that while the treatment may not cure Down’s Sydnrome, it could help to block out some of the life-threatening aspects of the disease:
“There are a lot of people with Down’s syndrome who are really near the threshold of being able to lead an independent life or hold down a job, and there are things that may be able to help them to achieve it.”