An inherited learning disability similar to autism – called Fragile X – could one day be treated with a pill, a new study suggests.
Using an experimental drug originally designed to treat cancer, researchers in the US found they were able to restore the memories of mice genetically engineered to have the currently incurable condition.
Fragile X is the most common form of inherited learning disability, affecting about one boy in 4,000 and one girl in 6,000.
Symptoms include a short attention span, over-activity, speech problems, extreme shyness and anxiety in social situations. However, those with the condition also tend to have a sense of humour and to be particularly sensitive to other people’s feelings.
The disability is caused by the mutation of a particular gene involved in the creation of memories. The researchers deleted that gene in the mice – making them forgetful – but then seem to have managed to completely restore their memory by giving them the cancer drug, called Nutlin-3.
While the research was carried out in mice, it is thought the drug could have a similar effect in humans.
The lead researcher, Professor Xinyu Zhao, who has been working on Fragile X for about a decade, stressed they were “a long way from declaring a cure” for Fragile X but described the results as “promising”.
“I’m just excited that maybe our basic research — in the lab, in the test tube and animal models – may yield information that will eventually help people,” she told The Independent.
“If you’ve met these parents and children, you really feel for them. You feel you want to make their lives easier and give them hope.
“I give them hope that somebody is working hard to solve the problem and just now I think maybe I can indeed do something to help them. For that [reason], it’s exciting.”
The mice’s memories were tested by putting two objects in an enclosure.
“Mice are naturally curious, so they explore and sniff each one. We take them out after 10 minutes, replace one object with a different one, wait 24 hours and put the mouse back in,” said Professor Zhao, of University of Wisconsin-Madison.
“If the mouse has normal learning ability, it will recognize the new object and spend more time with it. Mice without the [particular] gene don’t remember the old object, so they spend a similar amount of time on each one.”
The researchers, who reported their results in the journal Science Translational Medicine, found that mice with the deleted gene had the same powers of memory as normal mice after they had been given Nutlin-3.
Professor Zhao said it was more likely that a drug would be able to reduce the symptoms of the condition than provide an outright cure. However, she added there was research going on into genetic techniques that could one lead provide a cure.
Becky Hardiman, chief executive of the UK-based Fragile X Society, said the condition was relatively simple to diagnose but was “often misunderstood or overlooked, particularly for people who have a learning disability or autism”.
She said hopes had been raised in the past about promising research in mice that was later found not to have the same effect in humans.
However, when told about Professor Zhao’s research, she said: “That’s really exciting … it is a long way from mouse to man, but we’ll be very much excited to ‘watch this space’.”