| Autism causes are a complex mix of genetic and | | | | does not necessarily account for autism. |
| environmental factors that researchers have yet to | | | | Environmental Catalysts and Autism Genetics |
| fully understand. Studies of identical and fraternal | | | | Many researchers believe that the potential for |
| twins reveal that genetics play an important role in | | | | autism lies in genetics, but environmental factors are |
| autism. | | | | required to "trigger" the disease. Over time, a number |
| A Brief Description of Autism | | | | of environmental causes have been identified that |
| Defining autism is difficult, as the disorder covers a | | | | may act as catalysts for autism, including: |
| wide range of symptoms and severity can range | | | | - bacterial meningitis |
| from mild to debilitating. A neurological disorder, it | | | | - cytomegalovirus |
| causes impairment in social interaction and | | | | - developmental brain disorders |
| communication. A person with autism may have | | | | - fragile X syndrome |
| restricted interests or engage in abnormal, repetitive | | | | - lead encephalopathy |
| behavior. Depending on the severity of symptoms, it | | | | - rubella |
| causes mild to debilitating impairment. | | | | - some metabolic disorders |
| Autism is part of a group of related disorders | | | | - toxoplasmosis |
| collectively called autism spectrum disorders (ASDs). | | | | - tuberous sclerosis. |
| The autism spectrum, as its name implies, describes a | | | | These disorders are not considered definitive causes. |
| range of symptoms, rather than specific disorders. | | | | Most children who experience these conditions do not |
| Other ASDs include Asperger's syndrome, Retts | | | | develop autism. However these conditions may |
| syndrome and childhood disintegrative disorder, as | | | | interact with existing genetic factors, resulting in |
| well as pervasive developmental disorder, not | | | | autism. |
| otherwise specified. | | | | Vaccination and Disproven Autism Causes |
| Genetic Autism Causes | | | | Some suggested causes have proven false. The early |
| Most cases have no known cause, but the tendency | | | | theory that a distant or uncaring mother causes |
| for disorders of the autism spectrum to run in | | | | autism has long been disproven. |
| families suggests a genetic component. Families with | | | | More recently, an argument was made that the |
| one autistic child have a 3 to 8 percent chance that | | | | mercury preservative used in vaccinations caused |
| their other children will be autistic. | | | | autism. Despite significant research, no link between |
| Twin studies demonstrate the importance of | | | | vaccination and autism has ever been found. |
| genetics in establishing causes. If one identical twin | | | | Genetics, Autism and the Future |
| has autism, studies reveal a 30 percent chance that | | | | Most researchers doubt that causes can be traced to |
| the other twin is also autistic. | | | | a single gene. Instead, they believe that a number of |
| In addition to twin studies, autism research reveals | | | | different genes contribute to the development of |
| that families of autistic children have a much higher | | | | autism. Some autism experts have even speculated |
| rate of communication defects, impaired social skills | | | | that in the future, what we now label autism will be |
| or restricted interests, all of which are hallmarks of | | | | recognized as a group of similar, but separate |
| classic autism and fall within the autism spectrum. | | | | diseases. |
| Despite the strong evidence for genetic causes, | | | | It may take years to unravel the roles genetics and |
| parents of autistic children are rarely autistic | | | | environment play in autism, but the goal is attainable. |
| themselves, although they may display personality | | | | Understanding autism causes will help the search for |
| traits suggestive of autism. Genetics alone, then, | | | | effective treatments and better therapies for autism. |