Technique does not require a sample of amniotic fluid
By JUDY SIEGEL-ITZKOVICHDoctors perform surgery(photo credit: COURTESY SZMC)
Researchers at Jerusalem’s Shaare Zedek Medical Center have developed a new technique to discover hereditary diseases in young embryos and fetuses in natural pregnancies without the need to examine samples of amniotic fluid in the uterus.The team, headed by Dr. Gheona Altarescu, head of the preimplantation genetic diagnosis project at the hospital’s Medical Genetics Institute, calls their achievement a “breakthrough.”The results have been published in the Journal of Clinical Investigation , a leading journal on clinical trials.Working with Dr. David Ze’evi of the genetics department, the technique was used on eight couples who carry the Gaucher disease genetic disorder. The technique identified the cause of the disease in 100 percent of the cases and, as a result, the team will attempt to use it to predict other hereditary disorders. Characterized by bruising, fatigue, anemia, low levels of blood platelets and enlargement of the liver and spleen, Gaucher disease is caused by a hereditary deficiency of the enzyme glucocerebrosidase and treated by supplements of the enzyme in recombinant form.At present, when it is known that a couple carries a genetic disease, there are two ways to test the newly formed embryo – preimplantation diagnosis, testing a cell removed from the embryo before it is returned to the womb, and an invasive test called amniocentesis, or chorionic villus sampling. The new test can identify hereditary diseases with a simple test of the mother’s blood, which contains chromosomal material from the fetus. The technique for identifying Down syndrome by testing the mother’s blood was discovered by a Hong Kong researcher, Altarescu explained. But it could find only genetic defects passed on by the father, because it was difficult to differentiate between material that originated in the mother from that of the fetus. The new technique makes it possible to identify genetic material in the mother’s blood originating in the genes of both the mother and the father.“We started our research with Gaucher patients in cooperation with the head of our Gaucher clinic, Prof. Ari Zimran,” said Ze’evi. “We chose this group because these carriers are very accessible to us, as Zimran’s clinic is the largest in the world, and because the technique does not cause miscarriages in pregnant women.”Participants in the study underwent the blood test during normal pregnancies, and after they delivered, the babies were tested. The results of the test on the women’s blood turned out to be identical to those in the babies, Altarescu noted.