Featured Research

from universities, journals, and other organizations

Gene Mutations Not Always Expressed As Complete Disease

Date:
July 23, 1999
Source:
University Of North Carolina School Of Medicine
Summary:
Gene mutations tied to inherited diseases may cause only a portion of the expected disorder, according to scientists at the University of North Carolina at Chapel Hill. That such "minor mutations" can cause unexpected effects stems largely from recent findings in cystic fibrosis (CF).

CHAPEL HILL - Gene mutations tied to inherited diseases may cause only a portion of the expected disorder, according to scientists at the University of North Carolina at Chapel Hill.

Related Articles


That such "minor mutations" can cause unexpected effects stems largely from recent findings in cystic fibrosis (CF).

Writing in the July issue of Clinical Chemistry, Dr. Lawrence M. Silverman, professor of pathology and laboratory medicine at UNC-CH School of Medicine and Dr. Kenneth J. Friedman, a postdoctoral research associate, note that mutations in CFTR - the CF gene - can cause several distinct conditions having clinical similarities to CF. "And when we look at people with ICP and CBAVD, we find mutations in the same gene - the CF gene. So it's the type of mutation within the gene itself that causes the specific disease manifestations," he states.

Silverman and Friedman argue that atypical disease manifestations caused by minor mutations in the CF gene may have important implications for genetic screening and the field of molecular diagnostics in general.

At the annual meeting of the American Association for Clinical Chemistry in New Orleans, Wednesday, July 28, Silverman will discuss these implications when he speaks on national efforts to standardize genetic testing.

"Advanced molecular techniques provide a double-edged sword because they often detect sequence changes [mutations in genes] whose deleterious effects are by no means established," they write.

"When we start sequencing human genes, we may find some things that are not what we expected with that gene," Silverman says. "We have to appreciate that genes can operate at different levels. In CF, according to this new concept, certain mutations that are very severe can result in the typical disease phenotype. If other mutations are milder, more tissue-specific, you can have ICP or CBAVD. And there are still other mutations that will just create lesser sinus-related and pulmonary manifestations."

The situation also may extend beyond possible tissue-specific mutations. Mutations may be "developmentally specific." The consequences of the protein produced by a mutated gene would depend specifically on when that protein is active during the individual's development, Silverman says.

"But then it also might be mutation specific," he adds. With certain mutations we know how the protein is altered. But what if mutations create new functions for the protein, functions that may be deleterious?"

Thus, some mutations would not simply make the gene's protein function less effectively. The mutation would change the protein's function. "And that means the protein being produced has a new negative function," Silverman explains.

"We're arguing that mutations found with the powerful techniques for genotyping, will not always predict the classic disease phenotype, but a variant of it - as in the case of CF, with only a portion of the phenotype," he says.

Thus, several questions arise from this genotype-phenotype argument. In people with disorders having clinical similarities to a larger genetic disease, such as CF, do these disorders actually represent milder versions of that disease? Should such patients be examined clinically for subtle abnormalities of the disease that might otherwise escape detection? And should they be genetically screened for possible disease-related mutations?

"We see patients who come in for chronic pancreatitis whom we now test for CF mutations," the researcher says.

For Silverman and Friedman, the genotype-phenotype argument raises another question: "As the human genome project nears completion in 2003, what other genetic disorders will follow a similar paradigm?"


Story Source:

The above story is based on materials provided by University Of North Carolina School Of Medicine. Note: Materials may be edited for content and length.


Cite This Page:

University Of North Carolina School Of Medicine. "Gene Mutations Not Always Expressed As Complete Disease." ScienceDaily. ScienceDaily, 23 July 1999. <www.sciencedaily.com/releases/1999/07/990723083828.htm>.
University Of North Carolina School Of Medicine. (1999, July 23). Gene Mutations Not Always Expressed As Complete Disease. ScienceDaily. Retrieved November 21, 2014 from www.sciencedaily.com/releases/1999/07/990723083828.htm
University Of North Carolina School Of Medicine. "Gene Mutations Not Always Expressed As Complete Disease." ScienceDaily. www.sciencedaily.com/releases/1999/07/990723083828.htm (accessed November 21, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, November 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com
Ebola: Life Without School in Guinea

Ebola: Life Without School in Guinea

AFP (Nov. 21, 2014) Following the closure of schools and universities in Guinea because of the Ebola virus, students look for temporary work or gather in makeshift classrooms to catch up on their syllabus. Duration: 02:14 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins