Navigation Links
Clue to genetic cause of fatal birth defect
Date:10/9/2008

A novel enzyme may play a major role in anencephaly, offering hope for a genetic test or even therapy for the rare fatal birth defect in which the brain fails to develop, according to a study from researchers at the University of Illinois at Chicago College of Medicine.

The study appears in the October issue of the journal of Molecular Endocrinology.

In the U.S., 1,000 to 2,000 children are born with anencephaly each year. Most do not survive more than a day or two. Although anencephaly can sometimes be diagnosed through ultrasound, which picks up the malformation of the head, there is no genetic test, and its cause is unknown.

By breeding special "knockout" mice that were missing the gene for the enzyme called HSD17b7, UIC researchers found that such mice died on the tenth day of gestation with the severe lack of brain development that characterizes the human birth defect.

The failure of the mice to develop, as well as the extreme nature of the changes in the formation of the animals, was very surprising, said Geula Gibori, UIC distinguished professor of physiology and biophysics and principal investigator of the study. Mice that lack enzymes of similar function are born with subtle changes in their cognitive ability, but they survive.

The UIC researchers had previously discovered this novel enzyme and were focused on its role in converting the weak hormone estrogen into the more potent estradiol in the ovaries and its possible role in breast cancer.

Recent research has shown that the HSD17b7 enzyme has an additional role in the last steps of cholesterol biosynthesis. But because the fetus receives cholesterol from the mother during gestation, Gibori and her colleagues did not expect the enzyme to be of much importance to development, she said.

However, it appears that as the fetal mouse brain develops it forms a blood barrier, blocking maternal cholesterol from brain cells. The brain becomes dependent on the biosynthesis of its own cholesterol once this blood-brain barrier forms, at day 10 of gestation.

The UIC researchers established that in the fetus, the brain is the most important site for HSD17b7 expression and provided evidence that anencephaly may result from the loss of this enzyme.

"Creating a knockout mouse is a very laborious process," said Aurora Shehu, first author of the paper and at that time a graduate student in Gibori's laboratory. Mice with only one copy of the gene are produced and then interbred; one in four of their offspring should have no copy of the gene -- a "null" mouse.

"We expected null mice to be born and to be infertile, however, no null mice were born," said Shehu. "I was afraid I had made a mistake, and went back to the beginning, repeating the entire process, but still no null mice were born."

Shehu then began more painstaking work, performing in-utero genetic testing on entire litters -- often 10 to 12 fetuses per litter. She found that the null mice were there, but they were dying at day 10 of gestation, when the blood-brain barrier develops.

Gibori says the gene that is missing or defective in human anencephaly is not yet known, but the discovery that the deletion of HSD17b7 in the mouse causes anencephaly suggests this gene may be awry in the human disease.

"This opens up very exciting possibilities for understanding human anencephaly, and, perhaps, someday being able to provide a genetic test for the condition early in pregnancy -- and ultimately a therapy," she said.

As their next step, Gibori's lab plans to test human anencephalic tissue for a mutation in the HSD17b7 gene.


'/>"/>

Contact: Jeanne Galatzer-Levy
jgala@uic.edu
312-996-1583
University of Illinois at Chicago
Source:Eurekalert

Related biology news :

1. American College of Medical Genetics receives $13.5M NIH contract
2. Genetic finding implicates innate immune system in major cause of blindness
3. Study finds genetic variant plays role in cleft lip
4. Genetic Engineering & Biotechnology News reports on growing role of molecular diagnostics
5. Rare genetic disorder gives clues to autism, epilepsy, mental retardation
6. Childrens Hospital researchers identify genetic mutation that may predict organ rejection
7. K-State professors USDA research shows mad cow disease also caused by genetic mutation
8. How do race, genetics and health-care disparities affect spread of HIV?
9. Exploding chromosomes fuel research about evolution of genetic storage
10. Genetics reveals big fish that almost got away
11. Scientists discover major genetic cause of colorectal cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/2/2016)... 2, 2016 The Department of Transport ... the 44 million US Dollar project, for the , ... including Personalization, Enrolment, and IT Infrastructure , to ... production and implementation of Identity Management Solutions. Numerous renowned international ... Decatur was selected for the most compliant ...
(Date:5/20/2016)... , May 20, 2016  VoiceIt is excited ... with VoicePass. By working together, VoiceIt ...  Because VoiceIt and VoicePass take slightly different approaches ... increases both security and usability. ... about this new partnership. "This marketing ...
(Date:4/28/2016)... BANGALORE, India , April 28, 2016 ... subsidiary of Infosys (NYSE: INFY ), and Samsung ... global partnership that will provide end customers with a ... and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... for financial services, but it also plays a fundamental part ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. Hoffmann, former ... of the University of North Carolina Kenan-Flagler Business School effective June ... UNC Kenan-Flagler, with a focus on the school’s international efforts, leading classes and ...
(Date:6/24/2016)... , June 24, 2016 Epic Sciences ... detects cancers susceptible to PARP inhibitors by targeting ... cells (CTCs). The new test has already been ... in multiple cancer types. Over 230 ... damage response pathways, including PARP, ATM, ATR, DNA-PK ...
(Date:6/23/2016)... Wausau, WI (PRWEB) , ... June 23, 2016 ... ... probiotic supplements, is pleased to announce the launch of their brand, UP4™ Probiotics, ... supplements for over 35 years, is proud to add Target to its list ...
(Date:6/23/2016)... , June 23, 2016 Houston ... with the Cy-Fair Sports Association to serve as ... the agreement, Houston Methodist Willowbrook will provide sponsorship ... and connectivity with association coaches, volunteers, athletes and ... with the Cy-Fair Sports Association and to bring ...
Breaking Biology Technology: