Study Questions Genetic Screening for Treatable Diseases

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Prenatal diagnosis was performed in 68 of 90 (76 percent) pregnancies, and pregnancies were terminated in four of 16 (25 percent) cases of fetuses with Gaucher disease. Of the four aborted fetuses, two were predicted to have asymptomatic, or mild GD, and two were predicted to have moderate disease.

The study found that there were far fewer pregnancy terminations among couples who, in addition to receiving genetic counseling, also had medical counseling with a Gaucher disease expert -- one of 13 (eight percent) of pregnancies, compared with three of three (100 percent) among couples who did not receive medical counseling.

"With respect to the stated goal of carrier screening programs, the main practical outcome of GD screening was a 66 percent reduction in birth prevalence for moderate type 1 GD, for which the estimated frequency is 1 in 27,000, and a 15 percent reduction in the birth prevalence of asymptomatic or mild type 1 GD, for which the estimated frequency is 1 in 1,300. This was achieved through termination of pregnancy of fetuses either treatable or likely to be asymptomatic, and it is debatable whether this represents a true benefit," the study authors wrote.

They noted that the Israeli Medical Geneticists Association has recommended against Gaucher disease screening.

In an accompanying editorial in the journal, Dr. Ernest Beutler, of the Scripps Research Institute in La Jolla, Calif., said, "Not until clinicians and researchers better understand the factors that determine whether a patient homozygous for the N370S (GD) mutation will develop severe disease or none at all will screening for Gaucher disease become useful. Until then, screening for Gaucher disease will likely do more harm than good."

Zuckerman and his colleagues also questioned the use of genetic screening for other mild hereditary conditions.

"Applying the classic carrier screening paradigm to common, low-penetrance disease leads to inevitable dilemmas, and programs offering such screening should determine whether the true goal is knowledge and presymptomatic risk assessment or pregnancy termination of fetuses with a specified genetic status," the researchers wrote.

"Our results suggest that to avoid termination of pregnancies for generally mild conditions, even in a highly educated population, screening programs would require a combination of traditional, nondirective genetic counseling with medical counseling by professionals familiar with the specific diseases," they concluded.

More information

To learn more about Gaucher disease, visit the National Gaucher Foundation.