The causes of autism are yet to be fully understood, and the disorder has been linked both to genetic and to environmental factors. Recent research suggests that autism may develop in the womb, as early as the second trimester of pregnancy, adding to a growing body of evidence to suggests that the onset of the condition can occur before birth.
Autism is a developmental disability that affects a person for life, and is a result of neurological disorder. It affects how the person communicates, how they relate to other people and to social rules, and how they view the world around them. Autism is a spectrum, and can effect people in many different ways. Sometimes autistic people can live an independent life, while more severe cases can lead to obsessive, repetitive, and extremely difficult behaviour, which can require a lifetime of support.
Recent research published in the New England Medical Journal studied post-mortem brain tissue samples donated for research. They measured specific types of neurons in the brains cortex and were able to distinguish significant differences between the brains of children with autism, and the brains of those who did not have the condition.
10 out of the 11 children with autism, all aged between 2 to 16, were found to have irregular shaped neurons, resting in an obscure layer of the cortical, which formed dense patches. The areas of the brain where disruptions were found often correlated well with areas of the brain associated with autism, such as the temporal and frontal cortex, areas responsible for the use of language and the interpreting of social signals. Researchers found the irregularities in only one of the children in the control group who did not have autism.
The researcher, Eric Courchesne, explains that there are six layers to the human cortex, each layer containing a specific type of cell. Researchers were able to color code the specific cells in order to create a map of the areas of the cortex that they measured.
Ed Lein, co-author of the research paper and a developmental neurobiologist, suggests that the autism condition may develop, at least partially, in the womb. The parts of the cortex that were disrupted in the children with autism, tend to develop in the second trimester of pregnancy; previous research also suggests their development to occur between 19-30 weeks.
The study provides strong biological evidence for autism, which builds on an already existing body, but the researchers also suggest that conditions in the womb could also be a factor, highlighting again the link between environment and genetics, that has been so hard to pick apart during the study of the disorder.
Although the general body of research on the area demonstrates factors both environmental and genetic, the strongest evidence tends to point towards events before, and during birth. Strongly suggested links include parental age of conception, illness during pregnancy, and difficulties during birth. Factors such as these, as well as very early childhood trauma can increase the risk when combined with genetic predisposition.
One of the main problems with studying autism is that the disorder actually involves a vast spectrum, with individual and unique symptoms, making it difficult to study the whole range under one label. Nonetheless, the recent research, which suggests the autism may develop in the womb, could provide a step forward in understanding this complex condition. Researchers believe that an early diagnosis may open up the potential for appropriate early intervention, by working with the parts of the cortex that are functional, improving the life of the individuals that it affects.
By Matthew Warburton