Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mayo Clinic researchers discover genetic syndrome linked to inherited birth disorder

05.11.2003


Mayo Clinic researchers have identified a genetic syndrome -- an inherited birth disorder characterized by learning disabilities, facial malformations, impaired organs and mental retardation. It has been previously misdiagnosed or undiagnosed.



Researchers also discovered the syndrome’s genetic basis: a rearrangement of DNA called "microduplication." When microduplication occurs, DNA segments are repeated and this causes a surplus of genes. Microduplication is a little-studied mechanism underlying the origin of human diseases, and Mayo Clinic researchers are in the forefront of scientists producing evidence for its impact. Their work is made possible by the February 2001 completion of the federal Human Genome Project, the mapping of all the major genes in the human body. It has produced a database that describes the DNA sequences of the entire human complement of genes, which is estimated to be around 30,000 genes. The Mayo Clinic research, "Microduplication 22q11.2: An Emerging Syndrome," appears in the November American Journal of Human Genetics (73:1027-40)

Symptoms


Specific symptoms of this syndrome may include slightly misshapen faces and unusually widely spaced eyes, eyebrows placed higher than usual, and long, narrow faces, with irregularly shaped ears. Some patients have impaired hearing and speech, malfunctioning spleen and thymus gland, or heart defects. Other symptoms: faulty immune function and degrees of mental impairment.

The Significance of the Mayo Clinic Research

The work is important from the perspectives of genetic counseling, patient care and the history of medicine. The risk of inheriting this syndrome is 50 percent for a child with one parent affected by it and it’s highly likely that it runs in families. "This means it could make it a significant health concern," says Syed Jalal, Ph.D., a medical geneticist and professor at the Mayo Clinic College of Medicine and the study’s chief author.

While some symptoms can be treated, the syndrome cannot be cured until researchers discover a gene therapy to repair the microduplication errors. Precisely defining the new syndrome will help physicians care for their patients, but the work’s immediate importance is the insight it provides for genetic counseling. Says Dr. Jalal, "Microduplication now needs to be considered and investigated when some features or symptoms overlap with commonly occurring microdeletion disorders. This gives clinicians more information in providing the best care to patients and in understanding heritable diseases of a family’s genome." He adds that routine chromosome analysis can easily miss this duplication. Use of FISH (fluorescent DNA) probes is required.

This discovery also is important because it provides evidence for a class of new genetic errors known as "genomic arrangement" as a precondition leading to disease. Most often the opposite kind of errors -- microdeletion -- is studied and associated with disease. While the contributions of microdeletions to disease were well-known, Dr. Jalal was curious to know what would happen if the DNA were rearranged by the less-studied condition involving microduplication. "One of the things I’ve been concerned about for a long time is how structural abnormalities arise,’’ he explains.

"If you think about spontaneous miscarriages, 50 percent or more actually have a chromosomal problem. Recent large-population studies of miscarriages show that something like eight in 1,000 newborns have a chromosome problem. So chromosomal abnormalities are a part of the human experience, and are more significant than most people realize."

The Mayo Clinic research team collaborated with investigators in North Carolina, Maine, California and Georgia to define traits that constitute a new medical syndrome. They based their conclusions on detailed study -- from the position of genes in chromosomes to the placement of eyebrows on the face -- of 653 patients referred to the Mayo Clinic for evaluation of a known syndrome that shares some of the traits with the new syndrome.

This new syndrome has not yet been named, but it was often misdiagnosed as the DiGeorge syndrome -- which has many of the same symptoms. Yet this syndrome is genetically distinct. Of the 653 patients studied, 13 show microduplication of DNA within chromosome 22. DiGeorge patients have the opposite condition at that chromosomal site: microdeletion of DNA. Dr. Jalal says no one knows how common the new syndrome is. But it’s likely that it’s more common than DiGeorge syndrome, which occurs in one in 4,000 or 5,000 Caucasians.

Background Biology

Under study is a phenomenon within the chromosome known as "low-copy repeats." In low-copy repeats certain DNA sequences are present many times. They are distributed throughout the genome, and their role in giving rise to genomic rearrangements is under intense investigation in research laboratories throughout the world.

Knowing that chromosome 22 was vulnerable to rearrangement, Dr. Jalal theorized that rearrangement would lead to deletion as often as it did duplication. "Surprisingly, there was no real evidence for this,’’ he says. Previously, only three cases of microduplication disorders have been described in medical literature.

Bob Nellis | EurekAlert!
Further information:
http://www.ajhg.org/AJHG/journal

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>