Monday, January 09, 2006

Notícias da saúde: uma forma de avanço na genética

A mobile mission - Israeli researchers help stem mental retardation in Arab

David Brinn December 18, 2005

Schneider Children's Hospital

Tel Aviv University

Once a month, Lina Basel leaves her lab at the Schneider Children's Hospital in the Israeli city of Petah Tikva and travels an hour north to an Israeli Arab village near Hadera. There, the senior geneticist greets the nurses at the village's health clinic and begins seeing a steady stream of mothers who are coming to Basel for a blood test - one of the most important of their lives. Following three years of research in the village, an Israeli team including Basel has identified a gene that causes mental retardation, as well as a series of blood tests that can determine if adults are carriers of the gene or if a young fetus is likely to possess the gene. "We got the ideas for the study because a few Arab families from the village had come into our clinic with children suffering from mental retardation," Basel told ISRAEL21c. "We did some testing on them and came to the conclusion that the mental retardation was genetic - technically it is called autosomal recessive nonsyndromic mental retardation (NSMR." "We decided to study the phenomenon and asked the families to join the study and recruited others. We ended up with nine families from the village, which between them, had 16 children who were mentally retarded." Mental retardation is expressed in patients by motor developmental delay, speech inability, communication deficiency and dependency. The research team - led by Basel and Prof. Motti Shohat, director of the institute's Genetics Institute, initially located the defective gene on chromosome 19, after which they identified the gene itself. The biological function of the new gene called CC2D1A was previously unknown. Basel, Shohat and their team were awarded a prize in September by The Israel Genetics Society for their discovery of the gene. The results of the research were presented in October at the Conference for the American Society of Human Genetics in Salt Lake City, USA. The research also received an award from the Israeli Pediatricians Association. "Discovery of the gene causing mental retardation is very significant in the early diagnosis of the disease and contributes towards understanding the biological process leading to the disease's development. The finding is even more important relative to the extremely high incidence of the disease among the population at risk," said Shohat. According to the researchers, there are one in ten carriers of the abnormal gene in the at-risk population. Basel said that a system of diagnostic tests have been developed as a result of the discovery which determine if parents are carriers, and fetuses possess the gene. "If the parents are carriers of the gene, there's a 25% risk every time the woman gets pregnant. We also can perform fetal testing at 10-11 weeks for pregnant mother," said Basel. The mother first undergoes a genetic blood test. In the event that she is found to be a carrier of the genetic mutation, a carrier test is also conducted on the father. Should both spouses be carriers, a genetic test is conducted on the fetus, she explained. In order to make the testing more available to the families, Basel initiated the mobile clinic a year ago. "We travel once a month to the village to make available the tests in the most convenient manner. We work in conjunction with the women's health station and offer the services to every woman before during their pregnancies," she said. Basel said the families were immediately receptive to the program, and the families have taken the results and have made important decisions on whether to prevent or terminate pregnancies. "There was one family that was a little resistant, but they were also won over. I think the village is very happy with the results, and the fact that they can test each pregnancy. We've established a good relationship with them, especially the ones that are coming back with each pregnancy. We've gotten to know them, and they trust us." Basel explained that there are plans to expand the testing beyond the current village into other Israeli-Arab residential areas with a high incidence of mental retardation. "But, in the meantime, we're only doing it with this village. We're testing other populations now, but don't have the results," she said. Basel, who also works at the Molecular Genetics Laboratory at the Rabin Medical Center, immigrated to Israel in 1991 and did her PhD at Tel Aviv University in the lab of Professor Yossi Shilo, where, in 1995, she was part of a team that discovered a defective gene related to cancer called A-T. In her work at the Institute of Medical Genetics, Basel is part of a team that provides comprehensive genetic services to both campuses of Rabin Medical Center, the Schneider facility and to Geha Hospitals. The Institute is also a referral center for community clinics and other hospitals. But nowhere is her effect felt more powerfully than in the village where she is helping to stem the tide of mental retardation.