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Can High-Functioning Autism Be Inherited?

"Can autism (high functioning) be inherited? Our daughter was recently diagnosed, and now I'm thinking my husband may have the condition as well, they seem to have certain characteristics in common."

High-Functioning Autism (HFA) is a neurobiological disorder in which known areas of the brain are affected in ways researchers do not yet fully understand. HFA is considered to be inherited in a complex fashion (more complicated than disorders like color-blindness or Huntington’s disease).

The recurrence rate for the disorder in siblings of affected children is approximately 2% to 8% (much higher than the rate in the general population, but much lower than in single-gene diseases).

One study looked at extensive data in order to study some risk factors of autism (e.g., place of birth, parental place of birth, parental age, family history of psychiatric disorders, and paternal identity). Prevalence of autism among siblings of kids with Asperger’s was found to be 1.04%. The study found that (a) the risk of autism was associated with increasing paternal, but not maternal, age; and (b) the risk was twice as high if the mother had been diagnosed with a psychiatric disorder. 
 
==> Parenting System that Reduces Problematic Behavior in Children with Asperger's and High-Functioning Autism

Another study showed a positive correlation between repetitive behaviors in autistic children and obsessive-compulsive behaviors in parents.

Yet another study examined the family psychiatric history of 58 subjects with Asperger’s diagnosed according to DSM criteria. Three (5%) had first-degree relatives with Asperger’s; thirty-five (60%) had a family history of depression; and out of 64 siblings, 4 (6.25%) were diagnosed with Asperger’s.

As one mother (and wife) stated, “My husband was only diagnosed after our daughter. ‘It’s so common’, our psychologist told us. We now think his brother and sister are on the autism spectrum too. All are so alike. It answers so many questions. Our psychologist thinks it goes back at least 5 generations from family history, and we agree.”





Scientists are getting closer to finding a genetic basis behind autism spectrum disorders. Rett’s syndrome is an autistic disorder for which the exact genetic cause is believed to have been found. In HFA, studies suggest problems in several chromosomal (genetic) regions, including areas on the chromosomes 2q, 7q and 15q. While the 7q region is considered the most promising area of study, research studies involving this chromosome in HFA have failed to observe its linkage to this region.

For reasons physicians do not know, there are far more boys "diagnosed" than girls (although there may be as many girls with HFA as boys, males get diagnosed with the disorder more often). Researchers have evaluated whether or not HFA represents an X-linked genetic disorder (i.e., one passed down generally from a mother to a son). Unfortunately, there have been cases of father to son transmission of the disorder, which means that the disease can't be X-linked.

In at least one case, two parents with HFA had a child that also had HFA, but did not have a severe case of the disorder, nor did the child have autism. In another case, identical twins both had HFA, but this is not always the case.

While some researchers support the idea that at least a portion of HFA isn’t genetic at all, there have been no specific findings associating the disorder with any environmental condition, including a lack of association of the disease with pregnancy characteristics and pregnancy complications.


More resources for parents of children and teens with High-Functioning Autism and Asperger's:
 
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