The mechanism as to how abnormalities in brain development might lead to autism and behavioural disorders is being understood by scientists.
Research into Fragile X Syndrome - a genetic condition that is the leading known cause of autism - has discovered that critical phases in the brain's development may be mistimed in people with the condition.
The mistiming of key developmental stages may result in inappropriate communication between brain cells and could cause the symptoms experienced by Fragile X patients, such as hypersensitivity to touch and sound, as well as social withdrawal, hyperactivity and anxiety.
The study also found these changes in the brain's connections occur much earlier than previously thought, midway through a baby's development in the womb.
Scientists say that the study, published in the journal Neuron,
suggests there are key "windows" when treatments for Fragile X and autism could be most effective.
Fragile X syndrome is as common as cystic fibrosis - it affects around one in 4000 males and one in 8000 females worldwide. It causes intellectual disability as well as social, language and behavioural problems.
The research, conducted by scientists at Northwestern University in the USA and the University of Edinburgh, sought to identify ways in which the brains of people with Fragile X differ from those of healthy people.
Researchers used a mouse model of the condition to investigate how the regions of the brain responsible for processing sensory information - for example, touch - may develop differently in Fragile X patients.
The team believes that the changes they found in this area of the brain may be mirrored in other regions, explaining the range of symptoms experienced by people with Fragile X syndrome.
Professor Peter Kind, who led the study at the University of Edinburgh, said: "This research is important because it indicates when changes take place in the brains of Fragile X mice, which can be accurately projected to humans with Fragile X syndrome. We've learned these changes happen much earlier than previously thought, which gives valuable insight into when we should begin therapeutic intervention for people with these conditions. It also has implications for the treatment of autism since the changes in the brains of Fragile X and autistic people are thought to significantly overlap."