ABSTRACT
This chapter is concerned with the application of molecular (DNA) testing for the prenatal diagnosis of genetic disorders. From a population perspective, prenatal DNA testing is applied to a relatively limited number of families when compared to the prenatal diagnosis of chromosome aberrations for women of advanced maternal age. From the perspective of individual reproductive risk, however, for prenatal DNA testing of single gene disorders, this risk characteristically ranges from 25% to 50% versus a 0.5% to 5% risk of a chromosome aberration in the case of women 35 to 45 years of age at the time of delivery. From a diagnostic perspective, prenatal DNA testing represents a greater challenge due to the rapidly expanding number of disease entities identified through molecular technologies versus the limited number of laboratories experienced and qualified to provide such testing. In almost all cases of prenatal DNA testing, therefore, the obstetrician-gynecologist as well as the reproductive geneticist serves as counselor and coordinator between the at-risk couple and the laboratory performing the genetic analysis. It is the aim of this chapter to provide practical guidance to obstetricians, recognizing that detailed descriptions of laboratory techniques concerning DNA analyses are beyond the scope of this chapter.
