Prenatal diagnosis in the prevention of genetic disease

Prenatal diagnosis of chromosomal and many enzymatic metabolic diseases is now possible, with very low apparent risk. The use of this technique will have major impact on certain of the severely handicapping and untreatable conditions. For example, if all pregnant women over 40 yr were to have an amniocentesis, with selective abortion of the affected fetuses, about 20% of the cases of Down's syndrome, a leading cause of severe retardation, could be prevented. Amniocentesis must be planned well in advance, and the studies on the fluid must be carried out in a smoothly operating, specialized laboratory highly experienced in amniotic fluid culture and study. When a family is identified as being appropriate for amniocentesis, the physician should work with one of the major laboratories involved in amniocenteses and together they should plan carefully for all procedures. Although the risks are low, significant ethical problems exist for some families.