Around 5,500 people with severe developmental disorders now know the genetic cause of their condition, following a major nationwide study which will help improve diagnosis across the world.
More than 13,500 families from 24 regional genetics services across the UK and Ireland were recruited to the Deciphering Developmental Disorders (DDD) study, a collaboration between the NHS and the Wellcome Sanger Institute funded by Wellcome and the Department of Health and Social Care, and supported by the National Institute for Health and Care Research (NIHR).
All the families had children with a severe developmental disorder, which was undiagnosed despite prior testing through the NHS and likely to be caused by a single genetic change.
Lead author Caroline Wright, Professor of Genomic Medicine at the University of Exeter, said:
“Getting the right diagnosis is absolutely critical for families with rare conditions, which collectively affect around 1 in 17 people.
“Most of these conditions are genetic and can be diagnosed using the same genomic sequencing technology.
“The families in our study were desperate for answers, which can make a huge difference to clinical management and quality of life.”
The Wellcome Sanger Institute sequenced all the genes in the children’s and parents’ genomes to look for answers, and the search is still ongoing.
Combined with other high-tech methods, the researchers have so far been able to provide genetic diagnoses for around 5,500 children in the study.
The diagnoses were in more than 800 different genes, including 60 new conditions previously discovered by the study.
Around three-quarters of the conditions were caused by spontaneous mutations not inherited from either parent.
The researchers also found that the chances of success in getting a diagnosis was lower in families of non-European ancestry, reinforcing the imperative to increase research participation for under-represented groups.
Senior co-author Matthew Hurles, incoming Director of the Wellcome Sanger Institute and Honorary Professor of Human Genetics and Genomics at the University of Cambridge, said:
“Undiagnosed patients with rare genetic diseases have the most to lose if they are not given an opportunity to participate in research and if their data are kept in silos.
“Many of these diagnoses were only made possible through combining data across all diagnostic centres in the UK and Ireland.
“For some diagnoses, it was only through sharing data with international colleagues that it was possible to make a diagnosis.
“As these genomic technologies move into routine healthcare, ensuring that undiagnosed patients can still benefit from research on their data will remain incredibly important.”
Health Minister, Will Quince, added:
“We’re creating the most advanced genomic healthcare system in the world and this study is yet another step forward to revolutionising care for NHS patients.
“Using cutting edge, high-tech methods such as this offers the potential to better understand and more accurately diagnose rare genetic conditions so children can access treatment faster and potentially limit the impact of the disease on their life.”
