Cause of Autism 1

7/24/2019 Cause of Autism 1

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Causes of AutismAnd

Its Spectrum

CausesScientists don't know the exact causes of autism spectrum disorder (ASD),

but research suggests that both genes and environment play important roles


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Genetic factors

!n identical twins who share the exact same genetic code, if one has ASD,

the other twin also has ASD in nearly " out of #$ cases !f one sibling has

ASD, the other siblings have %& times the normal risk of also developing the

disorder esearchers are starting to identify particular genes that may

increase the risk for ASD

Still, scientists have only had some success in finding exactly which genes

are involved or more information about such cases, see the information

below about ragile syndrome and tuberous sclerosis

*ost people who develop ASD have no reported family history of autism,

suggesting that random, rare, and possibly many gene mutations are likely to

affect a person's risk Any change to normal genetic information is called amutation *utations can be inherited, but some arise for no reason

*utations can be helpful, harmful, or have no effect

+aving increased genetic risk does not mean a child will definitely develop

ASD *any researchers are focusing on how various genes interact with

each other and environmental factors to better understand how they increase

the risk of this disorder


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Environmental factors

!n medicine, environment refers to anything outside of the body that can

affect health -his includes the air we breathe, the water we drink and bathe

in, the food we eat, the medicines we take, and many other things that our

bodies may come in contact with .nvironment also includes our

surroundings in the womb, when our mother's health directly affects our

growth and earliest developmentesearchers are studying many environmental factors such as family

medical conditions, parental age and other demographic factors, exposure to

toxins, and complications during birth or pregnancy

As with genes, it's likely that more than one environmental factor is involved

in increasing risk for ASD And, like genes, any one of these risk factors

raises the risk by only a small amount *ost people who have been exposed


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to environmental risk factors do not develop ASD -he /ational !nstitute of

.nvironmental +ealth Sciences is also conducting research in this area

*ore information is available on their website

Scientists are studying how certain environmental factors may affect certain

genes0turning them on or off, or increasing or decreasing their normal

activity -his process is called epigenetics and is providing researchers with

many new ways to study how disorders like ASD develop and possibly

change over time

ASD and vaccines

+ealth experts recommend that children receive a number of vaccines early

in life to protect against dangerous, infectious diseases, such as measles

Since pediatricians in the 1nited States started giving these vaccines during

regular checkups, the number of children getting sick, becoming disabled, or

dying from these diseases has dropped to almost 2ero3hildren in the 1nited States receive several vaccines during their first 4

years of life, around the same age that ASD symptoms often appear or

become noticeable A minority of parents suspects that vaccines are

somehow related to their child's disorder Some may be concerned about

these vaccines due to the unproven theory that ASD may be caused by

thimerosal -himerosal is a mercury5based chemical once added to some,

but not all, vaccines to help extend their shelf life +owever, except for some

flu vaccines, no vaccine routinely given to preschool aged children in the

1nited States has contained thimerosal since 4$$# Despite this change, therate of children diagnosed with ASD has continued to rise

6ther parents believe their child's illness might be linked to vaccines

designed to protect against more than one disease, such as the measles5

mumps5rubella (**) vaccine, which never contained thimerosal

*any studies have been conducted to try to determine if vaccines are a

possible cause of autism As of 4$#$, none of the studies has linked autism

and vaccines

ollowing extensive hearings, a special court of ederal 7udges ruled against

several test cases that tried to prove that vaccines containing thimerosal,

either by themselves or combined with the ** vaccine, caused autism

*ore information about these hearings is available on the 1S 3ourt of

ederal 3laims' website

-he latest information about research on autism and vaccines is available

from the 3enters for Disease 3ontrol and 8revention -his website provides

information from the ederal 9overnment and independent organi2ations
http://www.niehs.nih.gov/health/topics/conditions/autism/index.cfmhttp://www.uscfc.uscourts.gov/omnibus-autism-proceedinghttp://cdc.gov/ncbddd/autism/topics.htmlhttp://www.uscfc.uscourts.gov/omnibus-autism-proceedinghttp://cdc.gov/ncbddd/autism/topics.htmlhttp://www.niehs.nih.gov/health/topics/conditions/autism/index.cfm


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Reference list

:A*A and Archives :ournals (4$##, :uly ;) 9enetic component of autism

spectrum disorders may be moderate compared to environment,

twin study suggests ScienceDaily etrieved *arch 4, 4$#& from

wwwsciencedailycom

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Cause of Autism 1