Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Whole exome sequencing identifies cause of metabolic disease

06.02.2012
Sequencing a patient’s entire genome to discover the source of his or her disease is not routine – yet. But geneticists are getting close.
A case report, published this week in the American Journal of Human Genetics, shows how researchers can combine a simple blood test with an “executive summary” scan of the genome to diagnose a type of severe metabolic disease.

Researchers at Emory University School of Medicine and Sanford-Burnham Medical Research Institute used “whole-exome sequencing” to find the mutations causing a glycosylation disorder in a boy born in 2004. Mutations in the gene (called DDOST) that is responsible for the boy’s disease had not been previously seen in other cases of glycosylation disorders.

Whole-exome sequencing is a cheaper, faster, but still efficient strategy for reading the parts of the genome scientists believe are the most important for diagnosing disease. The report illustrates how whole-exome sequencing, which was first offered commercially for clinical diagnosis in 2011, is entering medical practice. Emory Genetics Laboratory is now gearing up to start offering whole exome sequencing as a clinical diagnostic service.

It is estimated that most disease-causing mutations (around 85 percent) are found within the regions of the genome that encode proteins, the workhorse machinery of the cell. Whole-exome sequencing reads only the parts of the human genome that encode proteins, leaving the other 99 percent of the genome unread.

The boy in the case report was identified by Hudson Freeze, PhD and his colleagues. Freeze is director of the Genetic Disease Program at Sanford-Burnham Medical Research Institute. A team led by Madhuri Hegde, PhD, associate professor of human genetics at Emory University School of Medicine and director of the Emory Genetics Laboratory, identified the gene responsible. Postdoctoral fellow Melanie Jones is the first author of the paper.

“This is part of an ongoing effort to develop diagnostic strategies for congenital disorders of glycosylation,” Hegde says. “We have a collaboration with Dr. Freeze to identify new mutations.”

Glycosylation is the process of attaching sugar molecules to proteins that appear on the outside of the cell. Defects in glycosylation can be identified through a relatively simple blood test that detects abnormalities in blood proteins. The sugars are important for cells to send signals and stick to each other properly. Patients with inherited defects in glycosylation have a broad spectrum of medical issues, such as developmental delay, digestive and liver problems and blood clotting defects.

The boy in this case report was developmentally delayed and had digestive problems, vision problems, tremors and blood clotting deficiencies. He did not walk until age 3 and cannot use language. The researchers showed that he had inherited a gene deletion from the father and a genetic misspelling from the mother.
"Over the years, we've come to know many families and their kids with glycosylation disorders. Here we can tell them their boy is a true ‘trail-blazer’ for this new disease,” Freeze said. “Their smiles—that’s our bonus checks."

The researchers went on to show that introducing the healthy version of the DDOST gene into the patient’s cells in the laboratory could restore normal protein glycosylation. Thus, restoring normal function by gene therapy is conceivable, if still experimental. However, restoration of normal glycosylation would be extremely difficult to achieve for most of the existing cells in the body.

The research was supported by the National Institutes of Health and by the Rocket Fund.

Reference: M.A. Jones et al. DDOST Mutations Identified by Whole-Exome Sequencing Are Implicated in Congenital Disorders of Glycosylation, online first, Am. J. Hum. Gen (2012). doi:10.1016/j.ajhg.2011.12.024

Holly Korschun | EurekAlert!
Further information:
http://www.emory.edu

More articles from Life Sciences:

nachricht Research team creates new possibilities for medicine and materials sciences
22.01.2018 | Humboldt-Universität zu Berlin

nachricht Saarland University bioinformaticians compute gene sequences inherited from each parent
22.01.2018 | Universität des Saarlandes

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Thanks for the memory: NIST takes a deep look at memristors

22.01.2018 | Materials Sciences

Radioactivity from oil and gas wastewater persists in Pennsylvania stream sediments

22.01.2018 | Earth Sciences

Saarland University bioinformaticians compute gene sequences inherited from each parent

22.01.2018 | Life Sciences

VideoLinks Wissenschaft & Forschung
Overview of more VideoLinks >>>