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DNA study pinpoints 14 new childhood disorders

A major genetic study has uncovered 14 new disorders that affect children’s development.

The findings have enabled doctors to diagnose for more than a thousand children and their families affected by rare genetic conditions.

Diagnoses

Researchers say the information is helping doctors to provide better care for patients. It has also allowed families with the same genetic conditions to connect with each other and access support.

The insights will accelerate efforts to improve understanding of the diseases and could eventually lead to new therapies, the team says.

Rare conditions

Each year, thousands of babies do not develop normally because of errors in their genetic make-up. This can lead to conditions such as intellectual disability, epilepsy, autism or heart defects.

Many individual developmental disorders are so rare that the genetic causes are not known. This means that those affected do not receive a diagnosis.

Families search for a genetic diagnosis for their children, as this helps them understand the cause of their child’s disorder. A diagnosis can let parents know the risk of any subsequent children being born with the disorder, which can be an enormous help if they want a larger family.

Professor David FitzPatrickMRC Human Genetics Unit, University of Edinburgh

Gene analysis

The Deciphering Developmental Disorders study used the latest gene analysis technologies.

More than 4,000 families in the UK and Republic of Ireland have participated in the research. Each had at least one child affected by a developmental disorder.

Clinical symptoms

Experts analysed all 20,000 genes from the participants, looking for DNA mutations that might account for their condition.

The team also assessed the children’s clinical symptoms and combined the results to match up those with similar disorders and provide diagnoses.

Each of these disorders is incredibly rare, so the large number of patients in this study was crucial to diagnosis. An individual doctor may see only one case, but by collaborating with hundreds of NHS staff and researchers we were able to link children from clinics across the British Isles.

Dr Jeremy McRaeWellcome Trust Sanger Institute

DNA mutations

The research found that around a quarter of the patients in the study had new mutations that have already been linked to known developmental disorders.

This enabled the study team to diagnose the children affected with those conditions.

New disorders

Researchers also identified 14 new developmental disorders that were caused by spontaneous DNA mutations not found in either parent.

Overall, the team estimates that around one in 300 children born in the UK have a rare developmental disorder caused by a new genetic mutation. This adds up to 2000 children each year in the UK.

Older parents

They also found that older parents have a higher risk of having a child with a developmental disorder caused by a new DNA mutation.

The chances rose from one in 450 for 20-year old parents to one in 210 for those aged 45.

Major study

The study is led by the Wellcome Trust Sanger Institute and includes researchers from the Medical Research Council Human Genetics Unit at the University of Edinburgh. It is published in the journal Nature.

This study has the largest cohort of such families in the world, and harnesses the power of the NHS, with 200 clinical geneticists and 4,000 patients.

Dr Matt HurlesWellcome Trust Sanger Institute

Related links

Journal article

Deciphering Developmental Disorders

MRC Human Genetics Unit

Edinburgh Medical School