ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Does Autism have A Genetic Connection?

Updated on October 23, 2009

What is Autism

Autism is a brain (neural) disorder characterized by slow learning, impaired social, and communication development. All of these symptoms appear before the child has reached the age of three years.  Since autism affects many regions of the brain attempting to understand how it occurs is difficult. It also has some genetic basis, though the genetics involved are also quite complicated. Autism may be the result of genetic mutations or could be the result of complex common genetic variation. In other words the second cause might just be a "perfect storm" of typical variations in genetic material.

Autism is typically diagnosed when a child displays a triad of symptoms. These are:

  • Limited social interaction
  • Restricted communication
  • Extremely limited interests. The limited interests typically generate repetitive behavior

Photo courtesy WikiCommons
Photo courtesy WikiCommons

Idential Twin Studies

When one of a pair of identical twins develops autism the likelihood that the other twin will develop it are quite high. So high, in fact, that in 88% of the cases where one twin developed autism the other twin followed shortly after. Twins also displayed similar patterns of autism between them, with a similar degree of learning disability.

This is not the case with fraternal twins where they are no more similar than an older or younger sibling. In cases of fraternal twins thirty-one (31%) percent were likely to develop autism if the other twin was diagnosed with it.

Autism is highly individualized, with each victim of the disorder displaying specific symptoms. In identical twins these symptoms were very similar between the pair.

Of course these studies give a very strong genetic link to the disease. But some scientists think there may also be an environmental component; a combination of genetics and setting.

Of the twenty two (22%) of identical twins who did not develop autism within a year of their twin would likely never develop autism. This means that parents can stop worrying about the unaffected twin developing autism after a year.


Fraternal Twin Studies

As mentioned above fraternal twins are much less likely to develop autism if the first twin is diagnosed with it. With fewer than thirty-three (33%) following along behind the first twin to develop it. However, the likelihood that the second fraternal twin will develop autism extends out to four years; not one.

Study Basis

This study was conducted with two hundred seventy-seven pairs of twins. Of this group sixty-seven (67) were identical twins and two hundred ten (210) were fraternal twins.


Twin Types and Gender

Of course, identical twins are always the same gender.

However, in the case of fraternal twins additional information was garnered.

When one of the fraternal twin pair was female the previously non-affected twin developed autism about 20% of the time. in twin pairs where both were male the second twin to develop autism did so about 40% of the time.

Comments

Submit a Comment

  • LiamBean profile imageAUTHOR

    LiamBean 

    8 years ago from Los Angeles, Calilfornia

    Thanks for reading Peg.

  • PegCole17 profile image

    Peg Cole 

    8 years ago from Dallas, Texas

    Thank you for the interesting facts on autism. I've wondered what this was and your article has given me insight. Good information.

working

This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

Show Details
Necessary
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
Features
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Marketing
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Statistics
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)