Navigation Links
Gene's newly explained effect on height may change tumor disorder treatment
Date:8/11/2008

St. Louis, August 11, 2008 A mutation that causes a childhood tumor syndrome also impairs growth hormone secretion, researchers at Washington University School of Medicine in St. Louis have found.

The discovery provides new insights into an old mystery, revealing why patients with neurofibromatosis type 1 are frequently shorter than their peers. The surprising details have led scientists to consider modifying their search for treatments for the inherited disorder, which is caused by a mutation in the neurofibromin 1 (NF1) gene and is characterized by an increased risk of cancer.

"We've learned that the NF1 gene affects stature through a different pathway than the one we've previously focused on to understand cancers in patients with neurofibromatosis type 1," says Washington University neurologist David H. Gutmann, M.D., Ph.D., a Washington University neurologist who treats individuals with neurofibromatosis at St. Louis Children's Hospital. "Given that this second pathway has been linked to cancer in other contexts, we may need to consider the possibility that it is contributing to these tumors and alter our treatment goals accordingly."

The results appear online in the journal Human Molecular Genetics.

Neurofibromatosis 1 affects more than 100,000 people in the United States and is one of the most common tumor predisposition syndromes. The severity of the condition varies.

The NF1 protein, called neurofibromin, influences a number of different growth control pathways. Until now, much research focused on neurofibromin's effects on RAS protein activity, which is linked to cell growth, proliferation and cancer. Normally, NF1 deactivates RAS proteins. In its absence, scientists believe unchecked RAS can promote cancer development.

To learn more, Gutmann's lab created a line of mice in which stem cells in the brain do not make the NF1 protein. They found that these mice were significantly smaller than normal and failed to grow and gain weight after birth.

Balazs Hegedus, Ph.D., a postdoctoral researcher in Gutmann's laboratory, noticed that the pituitary glands, which produce growth hormone, also were unusually small in these mice. The amount of a second hormone that triggers growth hormone release was also greatly reduced.

"We wanted to know if we could blame this on RAS protein activity, so we generated new mice with normal levels of neurofibromin expression, but increased levels of RAS activation in brain stem cells," says Gutmann, the Donald O. Schnuck Family Professor of Neurology, and director of Washington University Neurofibromatosis Center. "However, those mice were normal."

NF1 also increases brain levels of cyclic AMP (cAMP), an important signaling molecule. Working with the same line of mice where stem cells in the brain do not make the NF1 protein, researchers fed pregnant mice and their newborns an agent that increased cAMP levels. The baby mice were closer to normal size, even though they still lacked neurofibromin in brain stem cells. Gutmann suspects the mice didn't completely return to normal because dietary supplementation of cAMP levels cannot match the natural ability of neurofibromin to control cAMP levels.

Gutmann is intrigued by the connection to cAMP. Research in other disorders has begun to build a number of associations between cAMP and tumor formation. Gutmann's laboratory and others have treatments in the works for neurofibromatosis 1 that restore the inhibitory effect neurofibromin normally has on RAS, but the new results may mean treatments are also needed to restore neurofibromin's effects on cAMP levels.

"What we've learned also may help us gain insight into other disease processes," Gutmann notes. "There are a number of other rare genetic abnormalities that cause short stature, and this same pathway may be involved."

To follow up, Gutmann plans additional studies to explore the role of the NF1 gene in the pituitary gland and the hypothalamus, a brain region that controls pituitary gland production of growth hormone.


'/>"/>

Contact: Michael C. Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
Source:Eurekalert

Related biology news :

1. Gene regulation, not just genes, is what sets humans apart
2. Interaction of just 2 genes governs coloration patterns in mice
3. Muscle mass: Scientists identify novel mode of transcriptional regulation during myogenesis
4. Study finds blocking angiogenesis signaling from inside cell may lead to serious health problems
5. Smoking turns on genes -- permanently
6. Genes, Environment and Health Initiative invests in genetic studies, environmental monitoring
7. Hebrew SeniorLife researchers search for aging, osteoporosis genes
8. UT Southwestern researchers identify hundreds of genes controlling female fertility
9. Genes and environment grant funds close look at nature-nurture overlap in common diseases
10. Jumping genes could make for safer gene delivery system
11. Genes from the father facilitate the formation of new species
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/30/2017)... , March 30, 2017  On April 6-7, ... Hack the Genome hackathon at Microsoft,s headquarters ... two-day competition will focus on developing health and wellness ... Hack the Genome is the first ... tremendous. The world,s largest companies in the genomics, tech ...
(Date:3/29/2017)... March 29, 2017  higi, the health IT company ... North America , today announced a Series ... acquisition of EveryMove. The new investment and acquisition accelerates ... tools to transform population health activities through the collection ... higi collects and secures data today on ...
(Date:3/24/2017)... The Controller General of Immigration from Maldives Mr. ... have received the prestigious international IAIR Award for the most innovative ... ... Maldives Immigration ... Algeen (small picture on the right) have received the IAIR award for ...
Breaking Biology News(10 mins):
(Date:10/10/2017)... , Oct. 10, 2017 International research firm Parks ... Strategy, will speak at the TMA 2017 Annual Meeting , October ... trends in the residential home security market and how smart safety and ... Parks ... "The residential ...
(Date:10/10/2017)... CALIFORNIA (PRWEB) , ... October 10, 2017 , ... ... technological innovation and business process optimization firm for the life sciences and healthcare ... BoxWorks conference in San Francisco. , The presentation, “Automating GxP Validation for ...
(Date:10/9/2017)...  BioTech Holdings announced today identification and patenting ... stem cell therapy prevents limb loss in animal ... that treatment with ProCell resulted in more than ... to standard bone marrow stem cell administration.  Interestingly, ... of therapeutic effect.  ...
(Date:10/9/2017)... ... ... At its national board meeting in North Carolina, ARCS® Foundation ... Physics and Astronomy, has been selected for membership in ARCS Alumni Hall of ... Breakthrough Prize in Fundamental physics for the discovery of the accelerating expansion of the ...
Breaking Biology Technology: