Autism Causes and Other Important Issues
What is Autism and what are autism causes?
Autism is a general term used to describe a group of complex developmental brain disorders known as Pervasive Developmental Disorders (PDD). The other pervasive developmental disorders are PDD-NOS (Pervasive Developmental Disorder – Not Otherwise Specified), Asperger's Syndrome, Rett Syndrome and Childhood Disintegrative Disorder. Many parents and professionals refer to this group as Autism Spectrum Disorders.
How common is Autism?
Today, it is estimated that one in every 110 children is diagnosed with autism, making it more common than childhood cancer, juvenile diabetes and pediatric AIDS combined. An estimated 1.5 million individuals in the U.S. and tens of millions worldwide are affected by autism. Government statistics suggest the prevalence rate of autism is increasing 10-17 percent annually. There is not established explanation for this increase, although improved diagnosis and environmental influences are two reasons often considered. Studies suggest boys are more likely than girls to develop autism and receive the diagnosis three to four times more frequently. Current estimates are that in the United States alone, one out of 70 boys is diagnosed with autism.
What are autism causes?The simple answer is we don't know. The vast majority of cases of autism are idiopathic, which means the cause is unknown.
The more complex answer is that just as there are different levels of severity and combinations of symptoms in autism, there are probably multiple autism causes. The best scientific evidence available to us today points toward a potential for various combinations of factors related to autism causes – multiple genetic components that may cause autism on their own or possibly when combined with exposure to as yet undetermined environmental factors. Timing of exposure during the child's development (before, during or after birth) may also play a role in the development or final presentation of the disorder.
A small number of cases can be linked to genetic disorders involved in autism causes such as Fragile X, Tuberous Sclerosis, and Angelman's Syndrome, as well as exposure to environmental agents such as infectious ones (maternal rubella or cytomegalovirus) or chemical ones (thalidomide or valproate) during pregnancy.
There is a growing interest among researchers about the role of the functions and regulation of the immune system in autism – both within the body and the brain. Piecemeal evidence over the past 30 years suggests that autism may involve inflammation in the central nervous system. There is also emerging evidence from animal studies that illustrates how the immune system can influence behaviors related to autism. Autism Speaks is working to extend awareness and investigation of potential immunological issues to researchers outside the field of autism as well as those within the autism research community.
While the definitive cause (or causes) of autism is not yet clear, it is clear that it is not caused by bad parenting. Dr. Leo Kanner, the psychiatrist who first described autism as a unique condition in 1943, believed that it was caused by cold, unloving mothers. Bruno Bettelheim, a renowned professor of child development perpetuated this misinterpretation of autism. Their promotion of the idea that unloving mothers caused their children's autism created a generation of parents who carried the tremendous burden of guilt for their children's disability.
Facts about Autism
Did you know ...Autism now affects 1 in 110 children and 1 in 70 boysAutism prevalence figures are growingMore children will be diagnosed with autism this year than with AIDS, diabetes & cancer combinedAutism is the fastest-growing serious developmental disability in the U.S.Autism costs the nation over $35 billion per year, a figure expected to significantly increase in the next decadeAutism receives less than 5% of the research funding of many less prevalent childhood diseasesBoys are four times more likely than girls to have autismThere is no medical detection or cure for autism
Prevalence vs. Private Funding Leukemia: Affects 1 in 1,200 / Funding: $277 millionMuscular Dystrophy: Affects 1 in 100,000 / Funding: $162 millionPediatric AIDS: Affects 1 in 300 / Funding: $394 millionJuvenile Diabetes: Affects 1 in 500 / Funding: $156 millionAutism: Affects 1 in 150 / Funding: $79 million
National Institutes of Health Funds AllocationTotal 2008 NIH budget: $30 billionOf this, only $118 million goes directly to autism research. This represents 0.3% of total NIH funding.
Rare Autism Spectrum Disorders
Rett syndrome is relatively rare related to autism causes , affecting almost exclusively females, one out of 10,000 to 15,000. After a period of normal development, sometime between 6 and 18 months, autism-like symptoms begin to appear. The little girl's mental and social development regresses—she no longer responds to her parents and pulls away from any social contact. If she has been talking, she stops; she cannot control her feet; she wrings her hands. Some of the problems associated with Rett syndrome can be treated. Physical, occupational, and speech therapy can help with problems of coordination, movement, and speech.
Scientists sponsored by the National Institute of Child Health and Human Development have discovered that a mutation in the sequence of a single gene can cause Rett syndrome as autism causes . This discovery may help doctors slow or stop the progress of the syndrome. It may also lead to methods of screening for Rett syndrome, thus enabling doctors to start treating these children much sooner, and improving the quality of life these children experience.*
Childhood Disintegrative Disorder
Very few children who have an autism spectrum disorder (ASD) diagnosis meet the criteria for childhood disintegrative disorder (CDD). An estimate based on four surveys of ASD found fewer than two children per 100,000 with ASD could be classified as having CDD. This suggests that CDD is a very rare form of ASD. It has a strong male preponderance.** Symptoms may appear by age 2, but the average age of onset is between 3 and 4 years. Until this time, the child has age-appropriate skills in communication and social relationships. The long period of normal development before regression helps differentiate CDD from Rett syndrome.
The loss of such skills as vocabulary are more dramatic in CDD than they are in classical autism. The diagnosis requires extensive and pronounced losses involving motor, language, and social skills.*** CDD is also accompanied by loss of bowel and bladder control and oftentimes seizures and a very low IQ.
*Rett syndrome. NIH Publication No. 01-4960. Rockville, MD: National Institute of Child Health and Human Development, 2001. Available at http://www.nichd.nih.gov/publications/pubskey.cfm?from=autism
**Fombonne, E. Prevalence of childhood disintegrative disorder. Autism, 2002; 6(2): 149-157.
***Volkmar RM and Rutter M. Childhood disintegrative disorder: Results of the DSM-IV autism field trial. Journal of the American Academy of Child and Adolescent Psychiatry, 1995; 34: 1092-1095.
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