Molecular Genetic Technology
The collection of single nucleotide and copy number variants within an individual forms a genetic backdrop that influences how a person looks, grows, and physiologically responds to stressors such as a disease or medication. High-frequency sequence variants in the population are part of the normal backdrop of the human genome and for the most part are not thought to have functional consequences. Overt genetic pathology, in contrast, usually arises from genetic variants that disrupt the normal expression or function of one or more genes. The old term mutation has been replaced by variant, which can be benign, likely benign, of unknown significance, likely pathogenic, or pathogenic. This chapter reviews the molecular (DNA-based) techniques available to detect, identify, or diagnose disease-associated variants, specifically pertaining to screening and diagnostic needs during pregnancy. The extent and specificity of the resulting information depend on the source of genetic material, as well as the testing platform employed. General benefits of genetic testing include identification of disorders for which in utero treatment may provide benefit, optimization of neonatal outcomes by planning appropriate delivery staffing and location, providing family preparation for caring for a child with a genetic disorder, the option of pregnancy termination, and providing reassurance when results are normal. With rapidly developing technologies at our disposal, reproductive and obstetric professionals have a responsibility to connect patients with resources to ensure full understanding of the benefits and limitations of various screening and diagnostic options. Exciting new technologies are in development and should continue to be held to high standards of scientific rigor and clinical validation before entering mainstream practice.
