Is Down Syndrome disappearing? Is that a bad thing? Brian Skotko asks these provocative questions in a recent article in the journal Archives of Childhood Diseases, With new prenatal testing, will babies with Down syndrome slowly disappear?.
The proportion of children born with Down Syndrome is declining rapidly. That’s not because the incidence of Down Syndrome is declining. The cause is the dramatic increase in prenatal testing and the high abortion rate for Down Syndrome babies. As Skotko explains:
…[W]omen are waiting longer to have children. Because advanced maternal age is associated with increased chances of having a child with DS, the birth incidence of DS would have been expected to climb. However, the worldwide birth incidence of DS has actually decreased from what it could have been … For example, in the U.S., there would have been a 34% increase in the number of babies born with DS between 1989–2005, absent prenatal testing. Instead, there were 15% fewer babies born, representing a 49% decrease between the expected and observed rates.
Down Syndrome is a chromosomal anomaly with a straightforward cause. Human beings have 23 pairs of chromosomes for a total of 46. Individuals with Down Syndrome have an extra chromosome for a total of 47. Chromosomes pairs are numbered and Down Syndrome is the result of an extra chromosome 21. The extra chromosome leads to effects of varying severity throughout the body. Down Syndrome individuals have mental retardation, distinctive facial features, low muscle tone and medical problems such as congenital heart defects.
A major genetic defect like an extra chromosome is relatively easy to diagnose by amniocentesis. More recently, we have developed less invasive methods of screening for Down Syndrome such as the triple test or quadruple test. Further improvements in prenatal testing are on the horizon. Skotko wonders if improved testing will further decrease the proportion of Down Syndrome children:
…Several factors suggest so. First, the new tests will be offered in the first trimester … Consequently, women will be able to receive a DS diagnosis and make a decision about the continuation of their pregnancies in private… Second, the new tests are noninvasive, carrying no risk to the fetus …
Thirdly, in countries like the U.K., where women are only offered CVS or amniocentesis if their screening test is deemed “high risk,” the new tests would afford everyone an opportunity to know definitively if their fetus has DS … Lastly, the new tests are projected to cost less than amniocenteses …
Stotko, who has a sister with Down Syndrome, laments these advances, under the dramatic heading “our genetic future.”
While DS might be the first genetic condition that can be definitively diagnosed in the first trimester on a population basis, others will undoubtedly follow… ACOG issued an opinion opposing obstetric practices that perform terminations based on fetal sex alone. Barring work-up for sex-limited genetic conditions, sex selection could be interpreted as “condoning sexist values” and creating a “climate in which sex discrimination can more easily flourish.” By contrast, in its support for DS prenatal screening, has ACOG endorsed a climate in which disability discrimination could more easily flourish?
Skotko has strong feelings on the subject, dramatically concluding
…Parents who have children with Down syndrome have already found much richness in life with an extra chromosome. Now is the time for the rest of us to discuss the ethics of our genetic futures.
Richness? The use of that term is patronizing to both parents and to people with Down Syndrome. It is patronizing to parents because it implies that the lifelong burden of caring for a disabled child should be perceived as “enriching.” It is patronizing to people with Down Syndrome by suggesting that their primary value is to enrich the lives of others.
Interestingly, Skotko pays very little attention to the myriad of genetic diseases for which testing and termination are also available. He does not advocate the “richness” of life with a child who has a terminal neurologic condition like Tay-Sachs, or the “richness” of life with a child who has similar but more serious chromosomal abnormalities like Edward’s Syndrome (extra chromosome 18) or Patau’s Syndrome (extra chromosome 13). Evidently these disorders are not “enriching” enough to justify his concern.
Skotko is right to raise these issues, but he is wrong to substitute his judgment for the parents who face these decisions. Raising a child with a serious genetic anomaly is a major burden, one that never ends and one that often gets harder as the years go by. It should be up to those parents to make the decision, and they should be entitled to the most advanced and least invasive technology with which to do so.
