The diagnosis of genetic disorders before birth

Genetic disorders account for a significant number of the health care problems in our society. Advances in therapy and educational opportunities for the handicapped have increased both the life span and quality of life for many of those affected by genetic disorders. Recent developments in clinical and laboratory genetics have made possible the better delineation of certain malformation and/or mental retardation syndromes, so that their mode of inheritance can be understood. This information enables the genetic counselor to predict the risk for occurrence of a large number of genetic disorders. Most genetic counseling is done, however, only after the birth of at least one affected individual has alerted the family to their predilection for having children with a genetic disorder. The carrier state of a certain number of genetic disorders can now be detected, so that even before the birth of their first child, a family can be forewarned that they are at increased risk. Previously this knowledge often influenced couples to decide against having any children. The advent of prenatal diagnosis of genetic disease, however, which was pioneered in the 1960s, allows specific diagnoses of inherited disorders in the fetus; parents no longer have only a mathematical risk figure for guidance. The technics which permit a preview of the genotype of the fetus with respect to a certain disorder constitute an exciting new field or medicine. They are not now available for use in routine pregnancies, but in high-risk situations the collaboration of the primary care physician and the medical geneticist can contribute significantly to the prevention of certain severely handicapping genetic disorders. The field is new and promises to offer much more in the future as more of the inherited disorders are biochemically characterized and become subject to prenatal detection.