Tuesday, April 29, 2014

Autism & Genetics

The past few months I have researched and spent every free minute that I had on ensuring that I know the special education laws like the back of my own hand. Now, since I know my education in that area, I am going to spend my time researching the genetic side of autism. It is obvious that genetics plays a huge role in our situation. Two kids. Both boys. Both with autism.

Since Trenton's diagnosis, I have found out that if your first born has autism, your next child only has a 7% higher risk to develop autism compared to a child that is born into a family with no children with autism. If you second child developed autism, then your future children have a 20-30% more chance of having autism.

I have also found in my research that you are more than likely to have a child with autism if ADD, ADHD, OCD, and schizophrenia is in the family. It has been a while but I have posted all of this information before.

The doctor that diagnosed Andrew talked to us a lot about the role of genetics. He said that the X Chromosome from the male determines not only the sex but also the developmental factor of your child. Scientist and researchers are linking this to the genetic side of autism in come cases.

Moreover, the new information that I am finding is very interesting and educational.  From time to time, I will focus on educating you on the genetics side of autism as I gather and understand the information myself.

The following is some very common information that I keep on coming across.


A major finding to emerge is that many cases of autism are caused by rare genetic mutations, which can be recognized currently in 15-20 per cent of cases and this is likely to increase as more studies are completed.

Inherited mutations
Some of the time, these mutations are inherited from the parents, but in many cases they are associated with new mutations – ones that arose de novo (afresh) in the generation of sperm or egg cells.

These de novo mutations, which are not carried by the parents, can give rise to sporadic cases of autism, with a genetic cause but no family history. It is now possible to screen for many of these mutations and to advise people about recurrence risks.

This is hugely important to couples with a child with ASD who frequently overestimate their risk of having another child with ASD.

Often couples choose not to have more children but if a child has been affected by a de novo mutation, the risk of another child being affected is no higher than the general population.

It is also clear that some families carry very high genetic risks for ASD, due to inherited mutations. 

Another area of my research I will focus on is the area that autism is more common in boys. The following explains why very well.

 According to a team of geneticists in the U.S. and Switzerland, it all boils down to what’s called the “female protective model.” This suggests that girls have a higher tolerance for harmful genetic mutations and therefore require a larger number of them than boys to reach the diagnostic threshold of a developmental disorder. With identical genetic mutations, then, a boy could show symptoms of ASD while a girl could show none.
But because the female mutation threshold is higher, when girls are diagnosed with ASD, they tend to fall on the more severe end of the spectrum.
Researchers believe the same dynamic could explain why more boys are diagnosed with ADHD, intellectual disabilities and schizophrenia. The findings were published Thursday in the American Journal of Human Genetics.

All in the Genes

Geneticists analyzed DNA samples from 16,000 boys and girls with neurodevelopmental disorders. They found that, on average, females diagnosed with ASD had 1.3 to 3 times more harmful genetic alterations than males diagnosed with the disorder.

The findings suggest that as the male brain develops, smaller and more subtle genetic changes can trigger autism spectrum disorders. Female brains require a greater number or severity of mutations before showing symptoms, so their symptoms tend to be worse.


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