Present status of intrauterine diagnosis of genetic defects.

Prenatal diagnosis of genetic disorders has received increasing attention during the past 
several years. Rapid expansion of our knowledge of the basis of 
genetic disease and the development of reliable diagnostic methods have led 
to rapid advances in the intrauterine diagnosis of a large number 
of inherited disorders. Prenatal diagnosis was initially used to determine the 
presence of Down's syndrome and other chromosomal abnormalities and for the 
determination of fetal sex in pregnancies at risk for a number 
of severe X-linked recessive disorders. Shortly thereafter, it became clear that 
the same techniques could be applied to the prenatal diagnosis of 
a number of the inborn errors of metabolism. Most recently, a 
number of new techniques have been developed that may prove to 
be of great value in the prenatal diagnosis of a number 
of severe congenital malformations that before now could not be diagnosed 
prior to birth. The goal of this review is to define 
the past achievements, future goals, and present limitations of intrauterine diagnosis. 
The first section will deal with the general approaches used in 
prenatal diagnosis of genetic disorders. This will be followed by a 
discussion of the specific applications of the basic techniques to the 
intrauterine diagnosis of chromosomal abnormalities and of the inborn errors of 
metabolism. Approaches to prenatal diagnosis of genetic disorders include amniocentesis, direct 
and indirect visualization of the fetus, analysis of maternal blood and 
urine, and sampling of fetal tissues. Applications of prenatal genetic diagnosis 
include X-linked recessive disorders, chromosomal abnormalities, inborn errors of metabolism, disorders 
of lipid metabolism, disorders of carbohydrate metabolism, disorders of mucopolysaccharide metabolism, 
disorders of amino acid metabolism, and miscellaneous disorders such as cystic 
fibrosis. These techniques provide some parents with methods for having children 
without fear of having a child with a specific deformity. In 
addition to the development of approaches which will increase the number 
of disorders detectable in utero, the potential for treatment of genetic 
disorders is unlimited. 