'Preimplantation Genetic Diagnosis 2018: Current Practice and Beyond', 9-10 November 2018
Page URL: https://www.bionews.org.uk/page_95003

Sperm DNA changes linked to autism

20 April 2015
Appeared in BioNews 798

A study has found a link between DNA methylation levels in sperm and an increased risk of autism in children, indicating that epigenetic changes could explain why the disorder appears to run in families.

Analysing semen from a small group of 44 men, the researchers identified distinct changes in the epigenome of sperm from men whose infants went on to show early signs of autism.

They also found that many of the genes around those sites were involved in neural developmental processes.

'The higher the methylation in the genes we looked at, the higher the score for observational risk for the autistic symptoms in the children,' explained co-author Professor Daniele Fallin of the Johns Hopkins University Bloomberg School of Public Health in Baltimore, USA.

Autism spectrum disorder (ASD) is a complex condition of varying severity and affects communication and social behaviour. It is thought to be influenced by a host of genetic and environmental risk factors, and it has been seen to cluster in families.

While there is evidence of a strong inherited link to the development of ASD, the genetics is complex and in many cases the causes remain unexplained. In this study, the researchers set out to identify whether epigenetic changes, rather than genes themselves, might affect ASD.

'We wondered if we could learn what happens before someone gets autism,' said Professor Andrew Feinberg, from the Johns Hopkins University School of Medicine and a lead author on the study. Professor Fallin added: 'If epigenetic changes are being passed from fathers to their children, we should be able to detect them in sperm.'

The researchers gathered semen samples from 44 fathers-to-be, who already had a child with a diagnosis of ASD, and mapped the methylation changes across 450,000 individual spots in their genomes.

One year after the birth of their children, the researchers then assessed the infants using the Autism Observation Scale for Infants (AOSI), which is thought to predict autism. Comparing the results, they found 193 sites where higher or lower methylation levels in the fathers' sperm DNA meant that the child had a high AOSI score, and hence was more likely to develop the condition.

To further verify their results, the researchers compared similar methylation data available from brain samples of 40 deceased people, half of whom had been diagnosed with autism. Out of 75 sites found in a particular region of the brain, only 18 showed the patterns that were detected in the study, suggesting that the causes of autism are likely to be more complex.

Speaking to the Mail Online, Dr Judith Brown, of The National Autistic Society said: 'This is a thought-provoking piece of research which adds a new angle to the discussion about the complex and substantial role genetics play in autism.

'But this is a small pilot study of 44 fathers, as recognised by the authors, and must be must be replicated on a much larger scale before any significant conclusions can be drawn about the causes of autism.'

The researchers now plan to explore how the fathers' environment might contribute to the condition.

SOURCES & REFERENCES
DNA changes could explain why autism runs in families, according to study
The Independent |  15 April 2015
DNA changes in sperm may help explain autism
NHS Choices |  15 April 2015
Paternal sperm DNA methylation associated with early signs of autism risk in an autism-enriched cohort
International Journal of Epidemiology |  14 April 2015
Paternal Sperm May Hold Clues to Autism
Johns Hopkins Medicine |  15 April 2015
Sperm 'may hold clues to autism': Link is found between father's DNA and symptoms
Mail Online |  15 April 2015
RELATED ARTICLES FROM THE BIONEWS ARCHIVE
7 November 2016 - by Helen Robertson 
Children with autism spectrum disorder have twice as many harmful mutations in their mitochondrial DNA as their siblings, a study has found...
1 February 2016 - by Dr Julia Hill 
A Chinese laboratory has created genetically modified monkeys that show symptoms of autism...
7 December 2015 - by Jessica Richardson 
Danish researchers have identified that weight gain and loss can result in different epigenetic markers in sperm, suggesting a possible explanation for why children of obese fathers are more prone to obesity themselves...
10 August 2015 - by Antony Blackburn-Starza 
Researchers in the United States have demonstrated how a gene mutation can contribute to a particular form of autism...
3 August 2015 - by Dr Linda Wijlaars 
Epigenetic variation can predict the risk of post-natal depression symptoms in women without a history of depression, researchers from the UK and US have found...
30 March 2015 - by Dr Charlotte Warren-Gash 
Children conceived with assisted reproductive technology may be twice as likely to develop autism...
16 March 2015 - by Sophie McLachlan 
Genes associated with autism have been linked to slightly higher cognitive ability when present in the DNA of non-autistic people...
9 March 2015 - by Sophie McLachlan 
A UK twin study estimates that between 56 and 95 percent of autism spectrum disorder cases are attributable to genetics...
2 February 2015 - by Isobel Steer 
Siblings with autism do not share the same contributory genetic factor in almost 70 percent of cases, a study has revealed....
3 November 2014 - by Siobhan Chan 
Scientists have linked 107 genes to autism, and 22 of these genes have a significant impact on the likelihood of developing the disorder, two studies published in Nature have shown...
HAVE YOUR SAY
Log in to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions


Syndicate this story - click here to enquire about using this story.