Are Genetics to Blame for Intellectual Disability

Author: Cardiff University
Published: 2014/10/22 - Updated: 2022/08/12
Peer-Reviewed: Yes
Contents: Summary - Main - Related Publications

Synopsis: Scientists join forces to unlock an untapped source of genetic information to better understand and treat children with Intellectual Disability. An estimated 1.5M people with Intellectual Disabilities are in the UK, and a significant number are children under 18. There is an increasing need to have a coordinated and systematic study to address this issue and ultimately new interventions to help children with Intellectual Disability and their families.

Intellectual Disability (ID)

Intellectual disability (ID) is a term used when a person has certain limitations in cognitive functioning and skills, including communication, social, and self-care skills. These limitations can cause a child to develop and learn more slowly or differently than a typically developing child. Intellectual disability can happen any time before a child turns 18, even before birth. According to the American Association of Intellectual and Developmental Disabilities, an individual has an intellectual disability if they meet three criteria:

  • IQ is below 70-75.
  • The condition manifests itself before the age of 18.
  • There are significant limitations in two or more adaptive areas (skills needed to live, work, and play in the community, such as communication or self-care).

Intellectual disability affects about 2-3% of the general population. Seventy-five to ninety percent of the affected people have a mild intellectual disability. Non-syndromic or idiopathic cases account for 30 to 50% of these cases. A genetic disorder causes about a quarter of cases, and about 5% of cases are inherited from a person's parents. Cases of unknown cause affect about 95 million people as of 2013.

Main Digest

Experts from Cambridge, Cardiff, and UCL (University College London) will be given unprecedented access to genetic information on intellectual disability from NHS Regional Genetics Centers across the UK as part of a first-phase study funded by the Medical Research Council (MRC) and Medical Research Foundation (MRF).

The main objective of the research, led by Professor David Skuse of the UCL Institute of Child Health, is to gain a better understanding of why the genetic anomalies that cause learning disabilities lead to behavioral problems in childhood and a heightened risk of later-developing psychiatric disorders in adolescence and adulthood.

Its main objective is to recruit over 10,000 participants, creating a resource of unparalleled size and detail on the associations between specific genetic risk factors, learning disability, and behavior.

"There are an estimated 1.5M people with Intellectual Disabilities in the UK, and a significant number of them are children under 18 years of age," according to Professor Jeremy Hall from Cardiff University's Neuroscience and Mental Health Research Institute and MRC Center for Neuropsychiatric Genetics & Genomics.

"While we know intellectual disability can be caused by events such as extreme premature birth, birth injury, or brain infections, research has found that minor chromosomal anomalies - known as copy number variations (CNV) - are strongly associated with children with an Intellectual Disability.

Intellectual Disability - or more commonly known as learning disabilities - usually appears before adulthood. The signs and symptoms are mainly behavioral, with children experiencing difficulties learning to talk, memory, and learning key social skills.

"The NHS picks up this vital information by a simple genetic test; however, until now, it has been an untapped source of information," said Dr van den Bree from Cardiff University's Institute of Psychological Medicine and Clinical Neurosciences.

"Using the genetic information, the team will recruit some 10,000 families. Focusing on behavioral adjustments in early to middle childhood, they will examine and report behavior and ability using behavioral adjustments, social circumstances, and medical history," she added.

Dr. Lucy Raymond, Reader in Neurogenetics from the Cambridge Institute for Medical Research at the University of Cambridge, who will lead the genetic investigations, points out that when a CNV is found in a child with an intellectual disability, families deserve to be told what the future holds for their child, and how they should best manage behavioral and educational issues to avert poor mental outcomes. Currently, that information is not usually available.

Dr. Raymond adds:

"Our research aims to rectify this current unacceptable situation by creating comprehensive genetic knowledge linked with detailed information about adjustment in childhood that will be accessible to clinicians managing children with an Intellectual Disability."

However, it's not just children that the research will use this information to help support.

"Many of the families who have children with rare chromosome abnormalities come to us for help, support, and advice. They tell us that there is a real gap in knowledge on the long-term consequences of these genomic disorders on mental health," according to Beverly Searle, Chief Executive Officer of the Charity, Unique.

"There is an increasing need to have a coordinated and systematic study to address this issue and ultimately new interventions to help children with Intellectual Disability and their families."

"That's why we have given our firm commitment to this key piece of research which will hopefully provide us with some much-needed knowledge to help those families looking for answers about their children and risk later life," she added.

The second phase of the research will examine the relatively high risk of serious mental illness in adulthood of children diagnosed with intellectual Disability. The Intellectual Disability and Mental Health: Assessing Genomic Impact on Neurodevelopment (IMAGINE) is funded by the Medical Research Council (MRC). The IMAGINE study is supported by key charities that help families with children with Intellectual disabilities.

Resources That Provide Relevant Information


This peer reviewed publication pertaining to our Cognitive Disabilities section was selected for circulation by the editors of Disabled World due to its likely interest to our disability community readers. Though the content may have been edited for style, clarity, or length, the article "Are Genetics to Blame for Intellectual Disability" was originally written by Cardiff University, and submitted for publishing on 2014/10/22 (Edit Update: 2022/08/12). Should you require further information or clarification, Cardiff University can be contacted at Disabled World makes no warranties or representations in connection therewith.

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