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w 26 | FRoucbursique cnrs I internactniorns alI LE m JaOgUaNRzinAeL Prenatal Screening: the New State of the Art One of the main areas of application of predictive medicine is antenatal pathology diagnosis. Prenatal examination techniques have rapidly evolved, making it possible to provide the earliest possible care for babies, and to prevent certain births in case of severe disorders. In France, nearly 70% of all congenital anomalies can now be detected, compared with 16% twenty years ago, and progress in genetics will no doubt further increase this percentage. A simple blood sample from the mother will soon make it possible to detect trisomy 21 in her unborn child. France’s national ethics committee (CCNE) has recently taken position in favor of this type of screening, which could greatly reduce the use of amniocentesis and its accompanying risk of miscarriage. At first, the test will only be offered to women at high risk, and will be extended to all pregnant women once costs go down. Beyond trisomy 21 detection, this new technique paves the way for broader prenatal screening. Today, physicians who suspect the presence of a disease only check for alterations of the gene or chromosome associated with that pathology. But the entire fetal genome can now be isolated from the mother’s blood as early as nine weeks into pregnancy. In the near future, full DNA profiles will be easier and less costly to obtain than partial sequences. car eful INTERPRET ATION Genetic testing yields information that can be extremely precious, but difficult to interpret with certainty. “For example, we know exactly which genetic mutations cause cystic fibrosis, but we cannot tell whether an unborn child will develop a severe or moderate form of the disease,” emphasizes Patrick Gaudray, a geneticist at GICC.1 Sometimes, the presence of a genetic anomaly only indicates a potential risk of developing a disease. Such is the case with diabetes and with certain cancers whose development is triggered by multiple factors, only one of which is genetic predisposition. Since the gene sequence analyses will be available at a very early stage of pregnancy, before the legal deadline for abortion, “many couples could be tempted to choose termination, even when the doctors consider the risk of disease to be low,” warns philosopher Pierre le Coz, from ADÉS.2 “This reaction is entirely understandable, but it could cause an increase in the number of abortions in France, at least transiently.” Some observers even see the potential for  eugenically-motivated abuse. to discl ose or not? What should be done with data on the genetic heritage of a future newborn? The CCNE’s recent advice to physicians is to be selective about the information they share with the parents. The child’s entire genome could be analyzed for parents who so desire, but they would only have access to information regarding serious and incurable diseases to avoid undue EUGENICS. A doctrine that advocates the improvement of the human genetic heritage by selecting parents with desirable traits and prohibiting reproduction among individuals considered to be inferior. 07 In addition to a simple ultrasound scan (shown here), many genetic tests can detect congenital anomalies. 07 © TISSKANANAT/Fotolia.com


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