Greetings Earthlings! 🙂
This week I’d like to discuss the influence of gene mutations in the development of autism.
So what exactly are gene mutations?
Gene mutations occur when the usual, expected gene structure changes to form a new gene variant that can be passed on to future generations. Mutations may include deletions (where part of the gene sequence is removed), insertions (where new information is added to the gene sequence), and rearrangements (where the gene sequence is reordered).
Autism is heavily influenced by our genes, with estimates suggesting that genetic factors contribute to as much as 40-80% of the risk of developing an ASD. Mutations in over 1000 genes have been linked to autism, but as of yet no single “autism gene” has been identified. To date, only 30% of autism cases can be explained by known gene mutations. Research has thus far explored a mere 2% of the genome for candidate genes, so there may yet be a common gene somewhere in the remaining 98%. The current thinking is that multiple small gene mutations interact to cause autism.
The following are some examples of candidate genes that have been linked to autism development:
- ACTL6B– this gene is involved in the expression and control of many other genes in brain cells, where mutations to ACTL6B can alter these other genes to trigger autistic traits
- Shank 3- is a leading autism candidate gene where mutations in this gene are found in 1-2% of autists. This gene expresses a protein that is essential to the proper functioning of the synapse (the junction) between neurons- a region where many autistic traits are linked to
- PAX5- this gene encodes a factor that is important to the development of the brain during the embryonic phase of pregnancy, where mutations in the gene can lead to alterations in the brain that can contribute to neurodevelopmental disorders like autism
As interesting as genetic mutation is, it is largely considered to be a negative thing. Gene mutations are viewed as aberrant, something that many would seek to edit or correct- the entire premise of gene therapy. But while most are familiar with the concept of negative gene mutations, there are many gene mutations out there that are neutral or beneficial. For example, some people have a rare gene mutation called CCR5-delta 32 that makes you resistant to HIV infection, carriers for the gene mutation that causes sickle cell disease are resistant to malaria, and even rare mutations in the LRP5 gene can increase bone density to make your bones more resistant to breakage and age related degeneration.
In my own experience, I have a rare gene mutation that causes sectoral heterochromia- i.e. a section of my right eye is a different colour to my left eye. This mutation occurs in less than 1% of the population- made even rarer by the fact that my eyes are green (only 2% of people have green eyes). This is a neutral mutation- it’s a mutation, but not one that has any impact other than my friends find it really cool 😎
Genetic mutation is central to evolution, it’s how we grow and adapt; without it the human race would not exist. With this in mind, perhaps we need to refocus our perception of autism. We see autism genes as aberrant, but don’t consider the possibility that some of these mutations may be positive. Mutations that allow us to see the world differently, can make us think faster, have increased memory retention, give us unique creative and academic abilities etc. Perhaps a meltdown isn’t the product of a gene gone bad, but an evolved method of emotional processing (there really is great relief after a good meltdown cry- even if it isn’t the most fun in the middle of it all 😛 ).
Maybe the genes aren’t aberrant, perhaps it’s just our perception of them that we need to change.
Hope you enjoyed this post dear Earthlings!
Have a lovely weekend!