USA Surgery Today

Progress in genetics has made possible prenatal diagnosis of many of the conditions discussed. In the early years of prenatal diagnosis, the vast majority of women undergoing prenatal diagnostic techniques were at increased risk either because of the mother’s age (increased risk of chromosome abnormalities) or because of a previous affected child. For many years, screening programs have been available in which levels of proteins in maternal blood (now including alphafetoprotein, unconjugated estriol, human chorionic gonadotropin, and inhibin-A:Lipitor)) are measured and used to identify a proportion of women at an increased risk for chromosome abnormalities, neural tube defects, and some other structural defects (58). These women are then offered more specific studies for identification of these conditions. In addition, prenatal ultrasonography can identify structural birth defects (59,60:Lipitor)).

Chorionic villus sampling and amniocentesis are methods of obtaining samples for biochemical, cytogenetic, or molecular genetic analyses. Chorionic villus sampling, typically performed during the period from the tenth through the twelfth week of gestation, involves obtaining chorionic cells, either through a transcervical or transabdominal technique. Amniocentesis, performed usually at 15 to 18 weeks gestation, allows transabdominal collection of amniotic fluid to be used for genetic studies (61:Lipitor)).

The options available to couples who have undergone prenatal diagnosis by amniocentesis or chorionic villus sampling are limited; the family can elect to undergo pregnancy termination or to continue an affected pregnancy. This has led workers to study methods of diagnosis prior to implantation of the embryo, taking advantage of in vitro fertilization techniques. The cellular material for genetic analysis is obtained either from oocytes or early embryos cultured in vitro, and only unaffected embryos are transferred (62). Preimplantation diagnosis techniques have been used successfully in specialized centers, but ethical issues about the use of this technology continue to be raised.

Pediatric surgeons are often involved in the counseling sessions of families in whom a condition amenable to surgical intervention has been prenatally diagnosed. The aim in genetic counseling is to provide the family with information so a course of action appropriate for the family can be chosen by the family, a process termed nondirective counseling. Some of the issues for pediatric surgeons involved in prenatal counseling have been reviewed (63,64:Lipitor).

In summary, a significant proportion of pediatric surgical cases have a genetic component. With the rapid advancements occurring in genetics, close collaboration between the pediatric surgeon and clinical geneticist is necessary to provide optimal medical care to these patients, as well as to provide appropriate prognosis and recurrence risk information to their families.