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How do we look for the genetic variants that contribute to the chance of developing ASD?

We do this through a process called genetic testing. Genetic testing allows us to look for differences in genes that may affect brain protein function

There are many types of genetic variants and genetic testing has become better and better at picking up these differences.

But genetic testing alone isn’t helpful without proper understanding or interpretation. That is the role of genetic professionals.

Clinical geneticists and genetic counsellors help families understand what the genetic variant is and how it affects the chance of developing ASD.

Before genetic testing, a child with ASD may be referred to a genetic clinic to be evaluated by a clinical geneticist and genetic counsellor.

This appointment would involve: a review of their developmental and medical history, a review of the family history

and a physical exam to look for physical differences (e.g. facial features, head size).

This information will help the clinical team determine if there are any non-genetic reasons that could contribute to the child’s ASD or if there may be genetic reasons that could explain the child’s ASD.

If there are genetic reasons that could explain the child’s ASD, genetic testing will be offered which requires taking a blood sample from the child and sometimes both parents.

Genetic testing may also be directly ordered by a non-genetic healthcare provider, like a developmental pediatrician, psychologist, or neurologist.

But how good is genetic testing at picking up different genetic variants in children with ASD?

Among children who have autism, approximately 25% have a genetic syndrome, which may affect other systems in the body. In other words, ASD is one of the many features of an underlying condition for these children.

The remaining 75% are non-syndromic, sometimes referred to as isolated ASD, where ASD is the primary condition.

Currently, genetic testing offered in the clinic can detect contributing genetic differences in up to 30% of children with ASD, and these children tend to have syndromic ASD.

But most of the time, genetic testing comes back with either no genetic results or uncertain genetic results (results from genetic testing will be covered in more detail in the next module).

However, genetic testing technology is getting better and better, and our understanding of genes involved in ASD is increasing due to research.

Hence, genetic testing may provide answers for more individuals with ASD in the future.

Now that you understand more about what genetic testing is and what the process is like, move onto the next module to learn about what results you can expect from genetic testing.