Nav: Home

Discovery of new mutations may lead to better treatment

June 14, 2019

Developmental disorders are neurologically-based conditions that affect the acquisition of specific skills such as attention, memory, language and social interaction. Although they have a genetic cause, this is often difficult to detect through standard genetic analysis of the parents. The mutation found in the affected child is therefore termed a 'de novo' mutation (DNM).

« Although many new developmental disorders have been identified in recent years, there are many more to be discovered. Identifying them means that we will be able to give an accurate diagnosis to more patients and therefore allow them to have appropriate treatment and care, » Ms Joanna Kaplanis, a PhD student at the Wellcome Sanger Institute, Hinxton, UK, will tell the annual conference of the European Society of Human Genetics today (Saturday).

In the largest study to date on developmental delay, the researchers analysed genomic data from over 31,000 parent-child trios obtained from the UK's Deciphering Developmental Disorders Project, GeneDx, a US-based genetic testing company, and Radboud University Medical Centre in The Netherlands. Analysis of these trios yielded more than 45,000 DNMs. They developed an improved method to test for the enrichment (over-representation) of damaging DNMs in individual genes. « We found 307 significantly enriched genes, 49 of which are novel. With all of these genes we were able to explain about 51% of the DNM burden in our dataset. We then modelled different underlying genetic scenarios to get an idea of where the remaining de novo burden lies and how we can go about finding it," says Ms Kaplanis.

About 40% of developmental disorders are caused by DNMs, equivalent to about one birth in every 295 in the UK alone. The prevalence increases with the age of the parents. The disorders usually become apparent during childhood and include such conditions as autism spectrum disorder, attention deficit hyperactivity disorder (ADHD), intellectual disability, and Rett syndrome. They may be mild, but in many cases they are severe, and those affected will need lifetime support. However, when they are unidentifiable making a decision on the best care for the affected child is difficult.

Given the size of the dataset, the researchers were not surprised to have been able to identify new genes. « However, we were expecting to be able to explain more of the DNM burden than we did. This means that half of the DNM burden in patients with developmental disorders still remains unexplained, » says Ms Kaplanis. « This fact alone gives us clues about where the remaining burden lies and why we do not yet have the capacity to discover the remaining genes. »

A possible explanation is that the DNMs in the genes as yet undiscovered are less penetrant, i.e. they present symptoms in fewer people. « We may need to adapt our system of gene discovery in order to capture these less penetrant genes, » says Ms Kaplanis. « Incorporating more data from healthy populations may help to try and build a better picture of what they might be. «

The researchers also hope to increase their sample size in order to try to detect ever more genes associated with developmental disorders. However, the identification of 40 new genes already provides valuable information to clinicians and to drug developers. « Returning a genetic diagnosis is important when deciding on the best treatment and care for an individual, as well as providing new drug targets in rare diseases," Ms Kaplanis will conclude.

Chair of the ESHG conference, Professor Joris Veltman, Director of the Institute of Genetic Medicine at Newcastle University, Newcastle upon Tyne, UK, said: "Developmental delay is often caused by new mutations arising during the formation of sperm or eggs. By combining data on new mutations identified in the DNA of more than 30.000 patients, the scientists could implicate a role for 49 new genes in developmental delay. This study shows the power of large-scale international collaboration to advance our understanding of this disorder and improve diagnostics as well as patient management."
-end-
Abstract no: PL2.4 Discovery and characterisation of 49 novel genetic disorders from analysing de novo mutations in 31,058 parent child trio exomes

European Society of Human Genetics

Related Genes Articles:

Insomnia genes found
An international team of researchers has found, for the first time, seven risk genes for insomnia.
Genes affecting our communication skills relate to genes for psychiatric disorder
By screening thousands of individuals, an international team led by researchers of the Max Planck Institute for Psycholinguistics, the University of Bristol, the Broad Institute and the iPSYCH consortium has provided new insights into the relationship between genes that confer risk for autism or schizophrenia and genes that influence our ability to communicate during the course of development.
The fate of Neanderthal genes
The Neanderthals disappeared about 30,000 years ago, but little pieces of them live on in the form of DNA sequences scattered through the modern human genome.
Face shape is in the genes
Many of the characteristics that make up a person's face, such as nose size and face width, stem from specific genetic variations, reports John Shaffer of the University of Pittsburgh in Pennsylvania, and colleagues, in a study published on Aug.
Study finds hundreds of genes and genetic codes that regulate genes tied to alcoholism
Using rats carefully bred to either drink large amounts of alcohol or to spurn it, researchers at Indiana and Purdue universities have identified hundreds of genes that appear to play a role in increasing the desire to drink alcohol.
Reading between the genes
For a long time dismissed as 'junk DNA,' we now know that also the regions between the genes fulfill vital functions.
The silence of the genes
Research led by Dr. Keiji Tanimoto from the University of Tsukuba, Japan, has brought us closer to understanding the mechanisms underlying the phenomenon of genomic imprinting.
Why some genes are highly expressed
The DNA in our cells is folded into millions of small packets, like beads on a string, allowing our two-meter linear DNA genomes to fit into a nucleus of only about 0.01 mm in diameter.
Activating genes on demand
A new approach developed by Harvard geneticist George Church, Ph.D., can help uncover how tandem gene circuits dictate life processes, such as the healthy development of tissue or the triggering of a particular disease, and can also be used for directing precision stem cell differentiation for regenerative medicine and growing organ transplants.
Controlling genes with light
Researchers at Duke University have demonstrated a new way to activate genes with light, allowing precisely controlled and targeted genetic studies and applications.

Related Genes Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...