Why did my child develop autism? It’s a question often asked by parents who have a child with the developmental disorder. As physicians, we try to address that question throughout our practice, but autism, in fact, is not a single condition; it is a spectrum of disorders. At one end we have a child who is non-verbal and cannot speak, so he uses technology to communicate his thoughts and his concerns, and if he gets upset enough, can become violent towards others or him/herself. At the other end of the spectrum, we have a child who is quite remarkable and gifted in mathematics, yet, when it comes to trying to have a conversation or being social, these things are for more difficult to him than others. What becomes confusing to many parents, is that both of these children have the same diagnosis of Autism Spectrum Disorder (ASD).
World Autism Awareness Month is an internationally recognised month starting on April 2 every year. It encourages people and organisations to take measures to raise awareness about people with Autism Spectrum Disorder (ASD) throughout the world. In celebration of World Autism Month, we look at misconceptions and new research in understanding the condition.
One of the concerns is whether or not there really is an epidemic of Autism; these days, one in 88 children will be diagnosed with Autism. The data shows an increase in prevalence at the turn of the 21st century. Is this a case of an increase in prevalence over time, or is it because we have now started labelling individuals with Autism by simply giving them the diagnosis when they were present before the criteria for diagnosis even evolved? In fact, at the latter part of the 20th century, legislation was passed in the United States (US) that actually provided autistic individuals with resources and access to educational material that would help them. With that increased awareness, more parents, paediatricians and educators learned to recognise the features of autism and as a result, more individuals were diagnosed and got access to the resources they needed. In addition, the definition has changed and evolved over time that now has a broader spectrum for the diagnosis.
What causes autism?
A common misconception is that vaccines cause autism, but let us be very clear, vaccines do not cause Autism. In fact, the original research that suggested that was the case, was completely fraudulent, it was actually retracted from the Lancet journal in which it was published and author of the study that sparked the storm, Andrew Wakefield, has since been stripped of his clinical and academic credentials. The institutes of medicine and the centres for disease control have repeatedly investigated this and there is no credible evidence that vaccines cause autism. Furthermore, one of the ingredients in vaccines called Thimerosal, which was thought to be the cause of autism, was removed from vaccines in 1992 and data shows that it did not have an effect on the prevalence of Autism.
Then, the question of what causes autism still remains. Just as autism is a spectrum, there may very well be no single answer, but a spectrum of causes. Based on data, we know that one of the associations is advanced paternal age. In addition, another vulnerable and critical period in terms of development is when the mother is pregnant. During that period while the foetal brain is developing, we know that exposure to certain agents can actually increase the risk of autism. Also, there are some infectious agents that can increase the risk of developing autism.
In addition to these environmental risk factors, genetics also have a significant role. Focusing on this factor is key because it is a cause of Autism that we can readily define and are able to better understand the biology and how the brain works so that we can come up with strategies to be able to intervene. One of the genetic factors that we do not understand however, is the difference that we see in terms of males and females. Males are affected 4:1 when compared to females with autism and to date, a cause for this discrepancy has not been made clear. We can look at a family with one sibling who has autism and determine if that can predict the possibility of another sibling having it.
When we compare autism with other conditions that we are familiar with, for example, cancer, heart disease and diabetes, genetics seems to play a larger role in Autism than it does in any of these other conditions. However, it is not clear if one gene or a combination of genes are responsible. In fact, in some individuals with Autism, it is one single determinant gene that causes the condition. In other individuals, however, a combination of genes in part, with the development process, ultimately determine that risk for autism. We do not know in any one person, which of those two answers apply and so research started digging deeper. How then do we identify what those genes are?
Certain individuals can have autism for a reason that is genetic, but not because Autism runs in the family. This is because, in certain individuals, genetic changes can take place through mutations not passed down from the parents. Such mutations can take place in the egg or sperm at the time of conception, but has not been passed down from generation to generation within the family. We can now use that information to understand and identify those genes causing autism in those individuals. With current research it was found that 25 per cent of cases were due to a single gene and 75 per cent of cases were due to 200-400 genes that can cause autism. This explains in part why we see such a broad spectrum in terms of its effects. Although there are that many genes, there is some method to the madness. It’s not simply random, but these 200-400 genes fit together in a pathway or network that starts to make sense in terms of how the brain functions. We are beginning to understand how these genes work together to determine neuronal function and interaction and how they control behaviour, both in autistic individuals and individuals without autism.
Early diagnosis is key. Being able to make that diagnosis in a susceptible individual at a small window period gives us the ability to transform and be able to impact on the growing and developing brain and this is critical.
Today, with all this research, we are now able to take infants and use bio markers such as eye contact and eye tracking to identify an infant at risk. Being able to screen on a very large scale will be very helpful in terms of being able to intervene at an early stage when we can have the greatest impact. Intervention can include medications, educational strategies and new technologies (like devices) to train the brain and make it more efficient. Yet, there is still a long way to go. As much as we know, there is so much more that we do not know. There is the need to use, as a community, our collective wisdom to be able to make a difference.
For more information on ASD please log on to the Autistic Society of Trinidad and Tobago’s Facebook page: https://www.facebook.com/autisticsocietytt/
Dr Visham Bhimull,
Family Physician
MBBS (UWI)
Diploma in Family Medicine(UWI)
healthplusthemag@gmail.com