Autism and Gene Mutation

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!

Aoife

Autism Through The Ages

Greetings Earthlings! 🙂

In this week’s post I’m going to briefly explore the history of autism.

So gather round for storytime! 😀

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As autism rates increase, many people have come to believe that the condition is relatively new. Whilst the clinical term may be in it’s infancy, autism can in fact trace it’s genetic lineage back through millennia!

Genetic research has shown that some of the key genes involved in the development of autism came from our shared heritage with the apes, predating the evolution from monkey to man (somewhere in the region of 7 million years ago).

Image result for evolution

Other related autism genes are slightly more “recent” than this, having come into existence over 100,000-years ago.

Whilst a third of autistic genes may come about through spontaneous genetic mutation, from this evidence we can see that autistic genes were inserted into the genetic code of our ancestors for a reason.

Interestingly in ancient times, people that displayed autistic traits were in fact highly revered. Such autistic traits as exceptional memory skills, creative thinking, observational skills, heightened senses and extensive knowledge in important areas such as plants and animals (i.e specialist interests), would all have been greatly valued in an ancient community. The incorporation of these skills within the group would have been essential to their survival.

Experts also believe that autistic skills such as memory and attention to detail may have contributed to the creation of ancient cave paintings such as this one:

How often we focus on the negatives of autism that we fail to stop and consider the reasons these genes exist. If they were a hindrance to the human race, why have they not been eradicated through millennia of evolution?

I think Temple Grandin sums it up pretty well here:

Image result for autism genes memes

And she would be right! 😉 Experts believe that autistic genes have been conserved to advance our intelligence. Variants of autistic genes have been linked to improved cognitive performance and the formation of new brain cells.

Such talented historical figures as Michelangelo, Mozart, Beethoven and of course, Albert Einstein, are all believed to have shown signs of autism- but history remembers them for their esteemed achievements, not their genetic quirks.

Something that we would all do well to think of when we commit autistic people to the annals of history in future.

So there we have it Earthlings, I hope you find this information as interesting as I found it 🙂 I could go on further buuuuttt I think I’ll spare you the clinical history of autism for another day 😉

Have a good weekend everyone! 🙂

Aoife

Can animals have autism?

Greetings Earthlings! 🙂

Today I’d like to explore something I’ve been wondering about a lot recently: can animals be autistic?

We’ve often been told how closely related human and animal genomes are, but what about our brains?

I often look at my German Shepherd and see a lot of autistic traits in him- he has ADHD and anxiety, behaves inappropriately, thinks creatively (he once buried a bone in a mattress) and never really grew out of his puppy brain despite recently turning 6!

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^^^Not my dog, but similarly bonkers! 😛 😉

Naturally, I could be imagining it (as a scientist it’s hard not to over analyse), but what does the evidence have to say?

In clinical research, there are a number of animal models which have been genetically bred to exhibit autistic traits including rats, fruit flys, monkeys and most commonly mice. These animals will have mutations in genes that have been linked to autism which causes them to exhibit some common autistic traits. In the mouse model for example, mice show signs of repetitive behaviours, deficits in social interaction and reciprocation, memory deficits and increased aggression.

But what about in nature?

There is very little evidence to suggest that animals can be autistic, however, a recent study by veterinary behaviorists in the USA has indicated that there is evidence of canine autism! 

 whoa shock waynes world waynes world 2 GIF

I know!

Maybe I should get my dog diagnosed… 😉

In fact, vets have considered the possibility of autism like symptoms in dogs since 1966!!

The 2015 study examined tail chasing behaviours in bull terriers in addition to running DNA analysis.  These researchers found that tail chasing was associated with trance-like behaviour and random outbursts of aggression in these dogs. In addition to this, tail chasing was more common in males than females- just like human ASD’s. This group also suggested that the physical features of these bull terriers (long face, high-arched palate, and large ears) could be indicative of Fragile X Syndrome-  a genetic condition where 15-60% of this population are additionally diagnosed with autism.

This study is not definitive, but it does open us up to the possibility that autism may naturally exist in the animal kingdom.

As autism can be difficult enough to diagnose in humans, you never know- other animals could quite possibly have autism, we’ve just never considered it! 🙂

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Aoife

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