Study links 26 novel genes to intellectual disability

April 11, 2017, Centre for Addiction and Mental Health
Credit: CC0 Public Domain

Researchers at the Centre for Addiction and Mental Health (CAMH) and Queen's University have identified 26 new genes linked to intellectual disability. Currently most patients with intellectual disability receive no molecular diagnosis, which significantly affects their health and shortens their lifespan.

The study, published online today in Molecular Psychiatry, has implications for the diagnosis and clinical care of those affected, and also adds to our growing knowledge of brain development and functioning. It may eventually lead to personalized treatments for affected individuals. Interestingly, some of the genes identified are thought to be connected with autism spectrum disorders.

"This is the largest study of its kind on to come out of North America," said Dr. John Vincent, team leader and Senior Scientist who heads the MiND (Molecular Neuropsychiatry and Development) Laboratory in the Campbell Family Mental Health Research Institute at CAMH. The study was jointly led with Prof. Muhammad Ayub of Queen's University.

More than one in 100 children worldwide are affected by intellectual disability, which is characterized by significant limitations in learning that also affect their day-to-day lives. Frequently, intellectual disability also accompanies symptoms of , and many genes have been found to be shared by the two illnesses.

The study involved 192 families from Pakistan and Iran with more than one affected family member. Intellectual disability is frequently caused by recessive genes, meaning that an affected child gets a defective copy of the gene from each parent.

The families in the study all had a history of marriage among relatives, which occurs quite commonly in communities in South Asia, the Middle East and Africa. Studying families with this background, and multiple affected individuals, can enable researchers to identify that would otherwise remain hidden.

The Canadian research team pinpointed mutations related to intellectual disability in half of these 192 families, in 72 different genes. The identification of 26 new genes adds to 11 new genes that the team had previously linked to intellectual disability.

Implications for diagnosis and care

One immediate implication of the study is to prevent future cases of intellectual disability, the researchers note. Unaffected family members and relatives could be genetically screened to see if they carry these mutations, and provided with counselling on the risks of "within family" marriages.

A broader goal is to develop diagnostic screening tools that are also relevant to populations in which "within " marriages are rare, such as Canada, USA, Japan, China and Europe. Ultimately, this information would be used to plan more personalized treatment.

While 26 genes may seem a substantial number, there are likely hundreds of genes that, when defective, may lead to intellectual disability. "The strategy we have used speeds up the process of identifying disease genes and of enabling diagnostic labs to deliver more accurate information for clinicians and families," says Dr. Vincent.

This strategy involves various genetic techniques, including microarray genotyping and whole exome sequencing, and studying families with a history of marriage among relatives.

"There's an opportunity now to further explore the functioning and biological pathways of these genes, and to help complete the picture of how the central nervous system works," says Dr. Vincent. "Knowing the involved is a big step forward, but understanding how they function is also crucial before we can start planning treatments or even cures."

Explore further: Two new genes linked to intellectual disability

More information: R Harripaul et al, Mapping autosomal recessive intellectual disability: combined microarray and exome sequencing identifies 26 novel candidate genes in 192 consanguineous families, Molecular Psychiatry (2017). DOI: 10.1038/MP.2017.60

Related Stories

Two new genes linked to intellectual disability

March 31, 2014
Researchers at the Centre for Addiction and Mental Health have discovered two new genes linked to intellectual disability, according to two research studies published concurrently this month in the journals Human Genetics ...

New form of intellectual disability discovered

April 27, 2012
Researchers at the Centre for Addiction and Mental Health (CAMH) led a study discovering a gene for a new form of intellectual disability, as well as how it likely affects cognitive development by disrupting neuron functioning.

New gene for intellectual disability discovered

July 15, 2011
A gene linked to intellectual disability was found in a study involving the Centre for Addiction and Mental Health (CAMH) – a discovery that was greatly accelerated by international collaboration and new genetic sequencing ...

Seven genes for X-linked intellectual disability

February 13, 2015
X-linked intellectual disability is a disorder that predominantly affects men and can have highly variable clinical manifestations. Scientists at the Max Planck Institute for Molecular Genetics in Berlin have found seven ...

Gene that causes intellectual disability when mutated finally identified

July 29, 2015
At least half of those with an intellectual disability across the world do not have a formal diagnosis. However, thanks to new DNA sequencing technology, along with the expertise and perseverance of University of Adelaide ...

Recommended for you

Short-course treatment for combat-related PTSD offers expedited path to recovery

January 23, 2018
Symptoms of Post-Traumatic Stress Disorder (PTSD) can be debilitating and standard treatment can take months, often leaving those affected unable to work or care for their families. But, a new study demonstrated that many ...

Priming can negate stressful aspects of negative sporting environments, study finds

January 23, 2018
The scene is ubiquitous in sports: A coach yells at players, creating an environment where winning is the sole focus and mistakes are punished. New research from the University of Kansas shows that when participants find ...

Social and emotional skills linked to better student learning

January 23, 2018
Students with well-developed and adaptive social and emotional behaviours are most likely to excel in school, according to UNSW researchers in educational psychology.

Study of learning and memory problems in OCD helps young people unlock potential at school

January 22, 2018
Adolescents with obsessive-compulsive disorder (OCD) have widespread learning and memory problems, according to research published today. The findings have already been used to assist adolescents with OCD obtain the help ...

People with prosthetic arms less affected by common illusion

January 22, 2018
People with prosthetic arms or hands do not experience the "size-weight illusion" as strongly as other people, new research shows.

Intensive behavior therapy no better than conventional support in treating teenagers with antisocial behavior

January 19, 2018
Research led by UCL has found that intensive and costly multisystemic therapy is no better than conventional therapy in treating teenagers with moderate to severe antisocial behaviour.

0 comments

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.