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|
University of Illinois at Chicago