UIC TO BEGIN PRENATAL DIAGNOSIS STUDY
Technique to Identify Defects in Single Genes
With $3.14 million in funding just awarded by the National Institutes of Health, UIC researchers are developing a powerful new prenatal diagnostic technique for detecting genetic abnormalities in the DNA of fetal blood cells found in the mother's bloodstream.
Investigations to date have focused on identifying instances of too many or too few chromosomes, causing birth defects such as Down syndrome, Turner syndrome and Trisomy 13.
In the new study, researchers in the UIC College of Medicine will also investigate a technique for identifying defects in individual genes within the chromosomes. Such defects can lead to serious disorders, including cystic fibrosis, sickle-cell anemia and Tay-Sachs disease.
Dr. Sherman Elias, head of the department of obstetrics and gynecology, will lead the study at UIC, in collaboration with Dr. Ronald Hoffman, chief of hematology/oncology. In 1991, Elias and a team of researchers were the first to demonstrate that genetic defects in the fetus could be identified in fetal cells isolated from maternal blood by a technique called fluorescent in-situ hybridization, or FISH, in which the cells' chromosomes were tagged with material that glows when fluorescently lit under a microscope. The team was able to identify aberrant numbers of the X and Y chromosomes and chromosomes 13, 18 and 21, which account for 90 percent of birth defects caused by chromosomal abnormalities.
With the new funding from the National Institute of Child Health and Human Development, the UIC researchers are now refining the FISH technique and methods for recovering the few fetal blood cells that trickle through the placenta into the mother's circulation. They will also expand their research into "culturing," or multiplying in the laboratory, these rare fetal cells found in the mother's blood. Culturing will enable the researchers to obtain enough DNA to conduct complete chromosomal studies and to try to detect mutations in single genes.
Prenatal diagnosis using fetal blood cells offers distinct advantages over the two current methods, amniocentesis and chorionic villus sampling (CVS). Both amniocentesis and CVS carry a small but real increased risk of miscarriage, about 0.5 to 1 percent. The new test would require only a routine blood sample from the mother and thus presents no risk to the developing fetus. Consequently, it could potentially be used by all women who wish to undergo the screening.
"Our goal is to find an accurate, safe and cost-effective means of prenatal diagnosis for all pregnant women," Elias said. "This in turn will increase opportunities for fetal therapy of single-gene disorders, including those causing developmental disabilities."
To test the accuracy of the technique, results for each blood sample will be compared with findings from amniocentesis or CVS. Because the technique is still in the research phase, none of the information in the study will be provided to patients or physicians for pregnancy management decisions.
UIC's funding for the study is part of a larger program supported by NIH with researchers at Baylor College of Medicine; DM-STAT, a statistics company in Boston; Thomas Jefferson Medical School; Tufts Medical School; the University of Basel in Switzerland; and Wayne State University. Meeting regularly, the institutions will work closely to develop collaborative methods that use a centralized system for data collection and analysis and will publish results jointly.
The UIC College of Medicine is the nation's largest medical school. One out of six Illinois doctors is a graduate of the college, as are 70 percent of the minority physicians practicing in Chicago. The college produces more medical school faculty than all but five schools in the country.
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