Epigenetic changes shed light on biological mechanism of autism

April 23, 2013, King's College London

Scientists from King's College London have identified patterns of epigenetic changes involved in autism spectrum disorder (ASD) by studying genetically identical twins who differ in autism traits. The study, published in Molecular Psychiatry, is the largest of its kind and may shed light on the biological mechanism by which environmental influences regulate the activity of certain genes and in turn contribute to the development of ASD and related behaviour traits.

ASD affects approximately 1 in 100 people in the UK and involves a spectrum of disorders which manifest themselves differently in different people. People with ASD have varying levels of impairment across three common areas: deficits in social interactions and understanding, repetitive behaviour and interests, and impairments in language and communication development.

Evidence from twin studies shows there is a strong genetic component to ASD and previous studies suggest that genes that direct brain development may be involved in the disorder. In approximately 70% of cases, when one identical twin has ASD, so does the other. However, in 30% of cases, identical twins differ for ASD. Because identical twins share the same genetic code, this suggests non-genetic, or epigenetic, factors may be involved.

affect the expression or activity of genes without changing the underlying DNA sequence – they are believed to be one mechanism by which the environment can interact with the genome. Importantly, epigenetic changes are potentially reversible and may therefore provide targets for the development of new therapies.

The researchers studied an epigenetic mechanism called DNA methylation. DNA methylation acts to block the genetic sequences that drive gene expression, silencing . They examined DNA methylation at over 27,000 sites across the genome using samples taken from 50 identical (100 individuals) from the UK Medical Research Council (MRC) funded Twins Early Development Study (TEDS): 34 pairs who differed for ASD or autism related behaviour traits, 5 pairs where both twins have ASD, and 11 healthy twin pairs.

Dr Chloe Wong, first author of the study from King's College London's Institute of Psychiatry, says: "We've identified distinctive patterns of DNA methylation associated with both autism diagnosis and related behaviour traits, and increasing severity of symptoms. Our findings give us an insight into the mediating the interaction between gene and environment in ."

DNA methylation at some genetic sites was consistently altered for all individuals with ASD, and differences at other sites were specific to certain symptom groups. The number of DNA methylation sites across the genome was also linked to the severity of autism symptoms suggesting a quantitative relationship between the two. Additionally, some of the differences in markers were located in genetic regions that previous research has associated with early and ASD.

Professor Jonathan Mill, lead author of the paper from King's College London's Institute of Psychiatry and the University of Exeter, says: "Research into the intersection between genetic and environmental influences is crucial because risky environmental conditions can sometimes be avoided or changed. Epigenetic changes are potentially reversible, so our next step is to embark on larger studies to see whether we can identify key epigenetic changes common to the majority of people with autism to help us develop possible therapeutic interventions."

Dr Alycia Halladay, Senior Director of Environmental and Clinical Sciences from Autism Speaks who funded the research, says: "This is the first large-scale study to take a whole genome approach to studying epigenetic influences in twins who are genetically identical but have different symptoms. These findings open the door to future discoveries in the role of epigenetics – in addition to genetics – in the development of autism symptoms."

Explore further: Twin study reveals epigenetic alterations of psychiatric disorders

More information: Wong, C.C.Y et al. 'Methylomic analysis of monozygotic twins discordant for autism spectrum disorder and related behavioural traits' Molecular Psychiatry (2013) doi: 10.1038/mp.2013.41

Related Stories

Twin study reveals epigenetic alterations of psychiatric disorders

September 21, 2011
In the first study to systematically investigate genome-wide epigenetic differences in a large number of psychosis discordant twin-pairs, research at the Institute of Psychiatry (IoP) at King's College London provides further ...

New research suggests birth weight plays a role in autism spectrum disorder

January 19, 2012
Although the genetic basis of autism is now well established, a growing body of research also suggests that environmental factors may play a role in this serious developmental disorder affecting nearly one in 100 children. ...

Study characterizes epigenetic signatures of autism in brain tissue

November 7, 2011
Neurons in the prefrontal cortex of individuals with autism show changes at numerous sites across the genome, according to a study being published Online First by the Archives of General Psychiatry.

Differences between human twins at birth highlight importance of intrauterine environment

July 15, 2012
Your genes determine much about you, but environment can have a strong influence on your genes even before birth, with consequences that can last a lifetime. In a study published online in Genome Research, researchers have ...

Balance tips toward environment as heritability ebbs in autism?

July 4, 2011
The largest and most rigorous twin study of its kind to date has found that shared environment influences susceptibility to autism more than previously thought.

Genomes of identical twins reveal epigenetic changes that may play role in lupus

December 21, 2009
Identical twins look the same and are nearly genetically identical, but environmental factors and the resulting cellular changes could cause disease in one sibling and not the other. In a study published online in Genome ...

Recommended for you

Latest research hints at predicting autism risk for pregnant mothers

September 21, 2018
Researchers at Rensselaer Polytechnic Institute—led by Juergen Hahn, professor and head of biomedical engineering—are continuing to make remarkable progress with their research focused on autism spectrum disorder (ASD). ...

Scientists reveal drumming helps schoolchildren diagnosed with autism

September 14, 2018
Drumming for 60 minutes a week can benefit children diagnosed with autism and supports learning at school, according to a new scientific study.

Overlapping copy number variations underlie autism and schizophrenia in Japanese patients

September 11, 2018
Common genetic variants may underlie autism spectrum disorder and schizophrenia across human populations, according to a study appearing September 11th in the journal Cell Reports. In line with previous studies in Caucasians, ...

New biomarker panel could accelerate autism diagnoses

September 6, 2018
Investigators at the UC Davis MIND Institute and NeuroPointDX, a division of Stemina Biomarker Discovery, have identified a group of blood metabolites that could help detect some children with autism spectrum disorder (ASD). ...

Depression strikes nearly one in five young adults with autism: study

August 31, 2018
(HealthDay)—Depression affects almost 20 percent of young adults with autism, new research shows, a rate that's more than triple that seen in the general population.

Kids with autism learn, grow with the 'social robot'

August 22, 2018
Robots may hold the keys to social success for kids with autism.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

88HUX88
not rated yet Apr 23, 2013

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.