Learning disability: finding genes, improving lives
First published on 11 March 2011
Updated on 26 April 2016
What did the project achieve?
“Our work has improved diagnosis of genetic conditions that cause children to have severe learning disabilities and seizures,” says Professor Jill Clayton-Smith of the University of Manchester. “Most of these conditions are difficult to diagnose just by examining children and taking a medical history.”
“We developed a new genetic test and offered it to 150 children, young people and adults with severe learning disabilities and seizures,” says Professor Clayton-Smith. “All of the children had already undergone extensive testing, but it hadn’t been possible to identify the cause of their problems – something that’s been all too common in the past.”
“Our findings enabled us to give nearly one quarter of the children a firm diagnosis for the first time in their lives,” says Professor Clayton-Smith. “With the new test, we can detect changes in around 60 genes at once, which is easier for children than testing for genes one by one, as well as being cheaper.”
“Our work has also improved understanding of what sort of symptoms children are likely to experience if they have a particular genetic change,” adds Professor Clayton-Smith. “As well as helping during diagnosis, this is important when making decisions about treatment and when predicting what the future holds for children as they grow into adulthood.”
This research was completed on 31 March 2014
Children with severe learning disabilities often remain dependent on others for round-the-clock care throughout their lives. It’s not always possible to diagnose the exact cause of a child’s disability, meaning important questions remain unanswered: Why is the child affected? What sort of treatments would suit them best? Are their parents at risk of having more children with the same disability? Researchers are developing new genetic tests, to improve diagnosis and help provide answers.
What's the problem and who does it affect?
Difficulties with diagnosis
Some children have very severe learning disabilities, which mean they will be dependent on others for round-the-clock care for the whole of their lives. They may be unable to speak, for example, or deal with everyday tasks such as getting dressed or feeding themselves.
Sadly, children with severe learning disabilities often suffer from other problems too. Some have seizures, they can have problems coordinating their movements and they sometimes repeat certain movements compulsively, endlessly wringing their hands, for example. The children can also have behavioural problems, such as autism.
The more everyone knows about the exact nature of a child’s learning disability, about what is causing their problems, the easier it is to give them the specialist care they need – the right sort of medication, physiotherapy or help to develop ways in which they can communicate and gain a degree of independence in their daily living.
However, diagnosis is often extremely difficult. A range of genetic tests are available, but choosing the correct one is hard. Testing is complex, time consuming, expensive and burdensome – many children have to have repeated blood tests, along with other investigations, such as MRI scans and lumbar punctures. Even then, results can be unsatisfactory and too many children are going undiagnosed.
What is the project trying to achieve?
What causes severe learning disabilities?
The researchers have been caring for children with severe learning disabilities for over 20 years. Both existing and new patients are taking part in this study, all of whom have an undiagnosed disability.
The researchers are looking for genetic changes that cause the children’s learning disabilities. They are also investigating whether or not the children inherited these changes from their parents (Some genetic changes are inherited, whereas others arise spontaneously). The researchers are using two state-of-the-art techniques, called genome-wide microarray analysis and Next-Generation sequencing.
In most cases, the researchers are using samples of DNA that have already been collected and stored. When these are not available, they are taking blood samples from patients and their parents.
The researchers are using what they learn to write guidelines for doctors on how best to diagnose severe learning disabilities in children. The guidelines will give advice on which genetic test to choose, depending on a child’s individual symptoms, and how to tell families about their child’s diagnosis..
What are the researchers' credentials?
|Project Leader||Professor J Clayton-Smith MBChB MD FRCP|
|Location||Department of Genetic Medicine, St Mary's Hospital, Manchester and the University of Manchester|
|Grant awarded||29 July 2010|
|Start date||1 January 2011|
|End date||31 March 2014|
|Grant code||SP4555, GN1778|
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The project leader, Professor Jill Clayton-Smith is a hospital consultant specialising in genetics. She has over 20 years’ experience of caring for people with severe learning disabilities and is recognised as a leader in this area of medicine. Together with other international experts, Professor Clayton-Smith and Dr Simon Ramsden have written guidelines on the diagnosis of Angelman syndrome, a severe type of learning disability.
Dr Simon Ramsden set up a specialised diagnostic service for children with Angelman syndrome in the UK. He has also been central to the development of national, and international, quality assurance systems for laboratories that specialise in diagnostic testing. The project team also includes Dr Jill Urquhart who has developed the microarray analysis facility within the Manchester Biomedical Research Centre.
Over the years, the researchers have already gathered detailed information on a large group of patients who have severe learning disabilities. This is a key resource. They also have access to the costly equipment that is needed for the state-of-the-art genetic tests that are being used in this project.
Who stands to benefit from this research and how?
Improving the diagnosis
The researchers hope to improve the lives of children who have a severe learning disability along with seizures, movement difficulties or behavioural problems. That includes children with certain rare syndromes, such as Angelman, Rett, Pitt-Hopkins and Mowat-Wilson syndromes.
The researchers are aiming to develop new genetic tests, along with guidelines on how to incorporate them into the diagnostic process. They hope their work will mean that more children receive an accurate diagnosis, with a clearer explanation of what is causing their disability.
Surveys have shown that having a diagnosis is very important to families. It improves the quality of genetic counselling that families receive - helping answer parents’ questions about why their child has got a learning disability and whether any children they, or their relatives, might have in the future are at risk. It can also relieve parents’ feelings of guilt.
An accurate diagnosis also makes it easier to ensure that a child receives the best possible care for them. It guides doctors and therapists in their choice of treatments and provides information that empowers patients and carers when they are trying to access support.
Further down the line, the researchers hope their work will help in the development of better treatments.