Autism has long been linked with heredity and genetic factors. Autism is a lifelong developmental difference, diagnosed in a growing number of children around the world. It is described by three main areas: differences in language and communication, differences in social interaction, and repetitive behaviours and focused interests.
Even though several genes have been identified, the etiology of Autism (how it develops biologically) is still not fully understood. Autism can seem unpredictable: it may affect one sibling and not another, or appear in a child when no one else in the family has an ASD diagnosis, and it is diagnosed around four times more often in males than females. In general, though, researchers agree that there is a genetic predisposition to Autism.
A study reported in 2015 identified the gene CNTNAP2 as one linked to Autism and to several other conditions, such as ADHD and dysthymic disorder (persistent low mood).
CNTNAP2, one of the largest genes in the human genome, carries the instructions for a protein called contactin-associated protein-like 2, which belongs to the neurexin family. Neurexins are proteins that help connect neurons (nerve cells) in the brain at synapses. A synapse is the junction where one neuron passes an electrical or chemical signal to another cell.
Note: Effect sizes are small and therefore could not be used for genetic screening
The study also concluded that CNTNAP2 is likely to be an autism-susceptibility gene. It found that a common variant in CNTNAP2 is associated with a slightly increased likelihood of autism.
Other studies have found that CNTNAP2 plays a role in early brain development. Researchers also found that mice without CNTNAP2 showed some characteristics similar to those seen in ASD. This adds to the evidence that this gene is one of many genetic factors involved in autism, rather than a single cause.
Note: this research news dates from 2015. Since then, researchers have identified hundreds of genes linked to autism, each usually playing a small part. There is no single “autism gene”, and genetic testing cannot diagnose autism.
I am Ash and I celebrate Neurodiversity! Growing up with an elder brother with severe Autism was tough – but it has also taught me essential life lessons. I don’t believe that people with Autism are necessarily or have any disorder (except in extreme cases). They are just different! And that is something to be proud of! I am passionate about helping other families who may have Autism conditions in their family. So please reach out and drop me a note. I will be glad to help 🙂
