The discoveries are similar to those of the first biological subtypes of cancer in the 1960s, which provided access to a better understanding of causes and effective treatments, cure and prevention, in addition to huge changes in public health polices, such as bans on smoking and asbestos. Over 200 biological subtypes of cancer have since been identified, such as breast cancer, lung cancer, skin cancer, colorectal cancer and prostate cancer. Like cancer, genetics, the immune system and the environment are believed to be factors in causes of autism.
Dr David Amaral, Research Director of the UC Davis MIND Institute in the USA, announced the discoveries at the Asia Pacific Autism Conference in Perth, Australia. The conference is the world's largest gathering this year of international experts on autism. Professionals from America, England, Belgium, Sweden, Kuwait, Singapore, India and Australia presented their peer-reviewed investigation discoveries at the conference.
Hosted by The Autism Association of Western Australia, the conference at the Burswood Entertainment Complex Convention Center in Perth, was attended by over 1,300 individuals from 22 nations and every state and territory in Australia.
The Western Australian Government is the primary sponsor of the conference, which was officially opened this morning by the Premier of Western Australia, Colin Barnett.
Dr Amaral's discoveries are the first publicly released major findings of the Autism Phenome Project, the biggest and most comprehensive evaluation of children with autism ever attempted. Beginning in 2006 the project is being conducted at the MIND Institute at the University of California, Davis (UC Davis). It is headed by Dr Amaral, Distinguished Professor of Psychiatry and Behavioral Sciences at UC Davis, and involves several investigators across eight fields.
Dr Amaral explained that his five-year investigation of 350 children with autism has uncovered two biologically distinct subtypes of brain development in autism, he said:
"One group of children has precocious growth of the brain. The pattern only appears in boys with autism and is mainly observed in children whose parents say they regressed into autism. The medical records of these children indicate that their brains began to become enlarged around 4 to 5 months of age, even though their autism did not appear until 18 to 24 months.
Many other children with autism, including all girls evaluated, appear to have a normal trajectory of brain growth, though their autism appears in the first 12 months. The biological cause of autism in these children is likely to be quite different from those with abnormal brain growth."
Dr Amaral told the conference:
"It is absolutely clear there are biologically distinct subtypes of autism. The hints that we have uncovered from monitoring the brain growth of children with autism is just the tip of the iceberg of biological features that will support the definition of biologically different types of autism. This is early days and it is impossible to define how many subtypes will ultimately be discovered.
Identifying, defining and investigating biological subtypes of autism is a key to understanding causes and progress towards effective treatment, cure and prevention.
I think there are probably many biological subtypes of autism. Until we start attacking each subtype we will not make progress towards prevention and more effective reduction in disability.
It is similar to the situation with cancer. If we were trying to cure all cancer at the same time it would be hopeless. Well, the same is true for autism."
Almost one out of 110 children born today have or will eventually have autism, according to the latest U.S. Government figures, in the 1980s the rate was 1 in 1,000. In Australia, the rate in 2007 was 1 in 160 children. There is no known cause or cure for autism. It is a neurodevelopmental disorder with relatively poorly understood biological origins. It is distinguished by a triad of symptoms:
- Impairments in social interaction
- Impairments in communication
- Restricted interests and repetitive behavior