"This research is one of the first clinical trials to assess whether a drug can improve brain function in people with an inherited disorder.
"The potential benefits of this treatment include an improved quality of life for affected patients and wider benefits for their families and carers.
"If it works it will benefit patients directly and could provide clues as to whether this class of drugs (called mTOR inhibitors) might have wider benefits in problems like autism."
More top news
Tributes have been paid to an ambulance driver killed in a crash with another ambulance in North Wales.
Tonight is expected to be clear and dry - though some parts of Wales will experience frost.
The RSPCA said the animal had found himself in "quite a predicament" after becoming trapped in the tight space.