Genes Environment Lifespan laboratory: Recent autism research

Dr Angelica Ronald, Department of Psychological Sciences, has been awarded the 2012 Spearman Medal for her work on autism spectrum disorders.

Autism is a neurodevelopmental condition that begins in early childhood. It is characterised by three main symptoms.

  1. Problems with social interaction: this usually involves a general tendency of not being interested in interacting with other people, not having many friends and not being interested in social input.
  2. Communication problems: these can range from having no language at all to having reasonable language skills but making unusual errors in communication style and not being able to maintain a two-way conversation.
  3. Restrictive, repetitive behaviours and interests.

For a diagnosis of autism to be made, all three symptoms must be present. Autism is usually diagnosed from the age of two years or older.

Fractionable Autism Triad Hypothesis

One of the key areas of Dr Ronald’s research has been the development of the Fractionable Autism Triad Hypothesis.  This suggests that, contrary to previous thinking, autism may not be caused by a single set of genes causing the whole condition, but that each symptom of the condition may be caused by largely different genetic and environmental risk factors.

Dr Ronald explains: “Nearly all of the previous research has looked at genetic and environmental risk factors with the assumption that they might be able to explain autism as a whole. Nobody was looking at what causes the individual symptoms. We hypothesised that a person with autism could have inherited three (or more) different sets of risk factors. There is now growing evidence that the genes that influence risk for social difficulties are largely different to those that influence risk for communications problems or restrictive repetitive behaviours.”

In order to find evidence supporting the Fractionable Autism Triad Hypothesis, Dr Ronald has conducted large-scale general population twin studies and molecular genetic analyses. She has found that many children display some symptoms of autism but don’t have a diagnosis of autism because they do not display the entire set of symptoms. A child may have just as many social impairments as a child with autism, but if they do not display the communications difficulties or restricted repetitive behaviours they will not be diagnosed with autism. Understanding the different genetic and environmental causes of the different characteristics displayed by children with autism would enable researchers to tailor interventions and treatments more effectively.

Multiple Psychiatric Diagnoses

It is thought that up to forty percent of children diagnosed with autism also have Attention Deficit Hyperactivity Disorder (ADHD), and a large proportion also have an anxiety disorder. Dr Ronald comments: “With psychiatric conditions it is almost the rule, rather than the exception, that there will be more than one condition diagnosed. We are looking at what it is that causes these multiple diagnoses in children with autism.”

The team are exploring three hypotheses.  First, they are testing whether the same genetic risk factors play a role in causing autism and ADHD and anxiety disorders.  Second, they are investigating whether these conditions may co-occur in the same individual in part due to similar environmental risk factors involved across conditions. For example, autism and ADHD are known both to be linked to complications during pregnancy and birth, so it could be environmental risk factors that increase the risk of a child having multiple conditions.  Finally, they are also exploring whether additional psychiatric conditions occur in children with autism as a result of the challenging symptoms involved. For example, if a child with autism experiences a lot of negative responses, they may develop anxiety because of their autism, rather than due to shared genetic or environmental underpinnings per se.

This research will lead to a better understanding of the causes of, and relationships between, multiple psychiatric conditions.

Genes, Environment, Lifespan

The aim of Dr Ronald’s research is to improve the understanding of the causes of autism and other psychiatric conditions. A better understanding of autism’s causes has a variety of implications. Once we understand the biological basis of a condition, more targeted treatments can be developed. It also means that autism could potentially be detected earlier, and intervention and treatment could begin earlier on, leading to better quality of life for the child affected and their family.

>> Find out more about Dr Ronald’s work at the Genes Environment Lifespan (GEL) Laboratory.

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