Autism spectrum disorders (ASDs) are a group of life-long developmental disabilities caused by an abnormality of the brain. ASD is characterized by problems with social interaction and communication skills, and by the need for sameness or repetition in behavior. ASD includes autistic disorder, pervasive developmental disorder - not otherwise specified (also known as atypical autism), and Asperger?s disorder.
Children with ASD require long-term care and services. Special education costs for a child with ASD are over $8,000 per year, with some specially structured programs costing about $30,000 per year, and care in a residential school costs $80,000 - $100,000 per year.
Little is known about what causes ASD, although genetic and environmental factors have been suggested. There is no cure for ASD, however, early and intensive education can help children develop skills to cope with the effects of ASD. Also, although available medicines cannot cure ASD, some may relieve symptoms associated with the disorders.
What is Autism?
Autism is classified as one of the pervasive developmental disorders of the brain. It is not a disease. Autism is a brain disorder that typically affects a person's ability to communicate, form relationships with others, and respond appropriately to the environment. Some people with autism are relatively high-functioning, with speech and intelligence intact. Others are mentally retarded, mute, or have serious language delays. For some, autism makes them seem closed off and shut down; others seem locked into repetitive behaviors and rigid patterns of thinking.
Although people with autism do not have exactly the same symptoms and deficits, they tend to share certain social, communication, motor, and sensory problems that affect their behavior in predictable ways.
Causes of Autism
In the majority of cases no specific underlying cause of autism can be identified. A variety of factors are associated with increased incidence of some forms of autism. These include infectious, metabolic, genetic, neurological, and environmental factors. There are many studies that support a genetic contribution. Family studies have shed the most light on this issue. Studies of identical twins, who have the same genetic make-up, have found about a 75 percent concordance rate (both twins have autism); fraternal (non-identical) twins have a 3 percent concordance rate. The risk of autism in siblings ranges from 2 to 6 percent. Finally, among families with autism there is a 10 - 40 percent increase in the diagnosis of other developmental disabilities, such as language delays and learning disabilities. The inheritance pattern is complex and suggests that a number of different genes may be involved.
It is generally accepted that autism is caused by abnormalities in brain structures or functions. Scientists are studying normal brain development to help them determine how abnormalities occur. The brain develops throughout the entire pregnancy cycle and continues to develop during the first few years after birth. Researchers have identified several different problems that can interfere with normal brain development. But identifying the causes of the problems and determining a cure are difficult tasks.
To date, genetic causes for one disorder commonly accompanying autism (Fragile X) and one autism-spectrum disorder (Rett Syndrome) have been identified and genetic "hotspots" for other forms of autism have been indicated. Fragile X is the most common genetically-inherited form of mental retardation currently known and produces many of the same behaviors and symptoms as autism. Rett Syndrome, which affects only girls, is a progressive brain disease that produces a loss of language/social skills that is similar to autism and is classified as a pervasive developmental disorder (PDD).
The MMR vaccine has not been shown to cause autism in children.
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