Scientists have developed a blood and urine test that can detect autism in children.
Researchers at the University of Warwick say the test, believed to be the first of its kind, could lead to earlier diagnosis of autism spectrum disorders (ASD) in children who could then be given appropriate treatment much earlier in their lives.
ASDs mainly affect a person's social interaction and communication, with symptoms that can include speech disturbances, repetitive and/or compulsive behaviour, hyperactivity, anxiety, and difficulty adapting to new environments.
As there is a wide range of ASD symptoms, diagnosis can be difficult and uncertain, particularly at the early stages of development.
Scientists said their research found a link between ASD and damage to proteins in blood plasma.
The researchers recruited 38 children who were diagnosed with ASD along with a control group of 31 other children between the ages of five and 12.
Blood and urine samples were taken from the children for analysis, with chemical differences observed between the two groups.
They found the most reliable of the tests they developed was examining protein in blood plasma, which found children with ASD had higher levels of the oxidation marker dityrosine (DT) and certain sugar-modified compounds called advanced glycation end products (AGEs).
Genetic causes are thought to be responsible for around a third of cases of ASD, while the rest are believed to be caused by a combination of environmental factors, mutations, and rare genetic variants.
The next research steps will be to repeat the study with further groups of children to confirm the good diagnostic performance and to assess if the test can identify ASD at very early stages.
Researchers believe their new tests could reveal yet to be identified causes of ASD.
The research is published in the journal Molecular Autism.