Is autism hereditary?

Question

I just want to know, say I have a cousin who is autistic, are the odds higher that one of my children will have it?

Answer 1

Hi Lynx,

May I know where you got the info that autism is carried by X chromosome. Could you kindly furnish the reference please.

Hi Bill,

As for the question, yes, genetics most certainly play a role (but *not* the only role) in autism. Siblings of autistic have 5% (one in every 20 cases) chance of growing autism themselves. It is of course a higher chance than in the general population. Both the "neurotypical" parents may pass it onto their children.

To give you a ref.

http://news.bbc.co.uk/2/hi/health/6369347.stm

"Experts have now located a region of one chromosome - 11p - and a gene called neurexin 1.

Neurexin belongs to a family of genes that help nerve cells communicate and the scientists now believe these play a critical role in autism spectrum disorders.

The work began five years ago in 2002, when scientists pooled their research resources and expertise and formed the Autism Genome Project."

Also, you may find the following piece interesting:-
"Older fathers 'raise autism risk'"
http://news.bbc.co.uk/2/hi/health/5313874.stm

I have recently read that scientists have come with the
mechanism to screen couples so as to predict whether or not
their [future] children would run the risk of having autism.
Cannot recall the exact ref. though.
Try googling at http://scholar.google.com/ for academic papers and scientific researches carried out in this field.

Hope this helps a little.

Cheers,
Anna.

Answer 2

Great answer Anna!

Siblings of an autistic child have a significantly greater chance of being autistic, but that drops significantly when it comes to cousins.

"The sibling risk of autism is 50 to 100 times greater than the risk observed in the general population­, a difference that implies genetic factors."
But . . .
"There might be six or more genes that have to come together in one individual in the right form to lead to autism,"
http://faculty.washington.edu/dawson/CurrentResearchActivities/Genetic.html
So you might have one or two of the genes - not enough to pass autism on to your child.

And, to repeat what Anna said, autism is not 100% genetic.
If my niece (low-functioning autism) had an identicical twin, the odds would be something like 60-70% her twin would also have low-function autism, up to 90% if you include high-functioning autism. If my neice was high-functioning the odds would probably be lower that her twin would be on the spectrum.

So your odds of having an autistic child are probably only fractionally higher than the general population.

Answer 3

Scientists aren’t certain what causes autism, but it’s likely that both genetics and environment play a role.



There are various classifications and degrees of autism. Some are unable to talk conversationally, while others have virtually no ability to speak.

Autism varies widely in its severity and symptoms and may go unrecognized, especially in mildly affected children.

Many people with Autim also have unusual ways of learning, paying attention, or reacting to different sensations. The thinking and learning abilities of people with Autim can vary – from gifted to severely challenged.

Autim begins before the age of 3 and lasts throughout a person's life. It occurs in all racial, ethnic, and socioeconomic groups and is four times more likely to occur in boys than girls.

Answer 4

Yes, autism is carried on the X chromosome, there for if you as a male and do not have it, you don't carry it and can not pass it on to children

This is because males have and XY chromosome and you can not be a carrier, you either have it or you don't. Females are XX so they can show no signs of autism but still have a 50% chance to pass it onto her children.

Answer 5

no