Facts of Life

Facts of Life:
Issue Briefings for Health Reporters
Vol. 11, No. 6
June 2006

Genes, Screens and a Healthy Future

The Issue

Psychological Costs

The Facts

Testing Kids for Adult Diseases

Expert Sources

References

The Issue:

The gene looms large in medicine's future, but genetic screening has already made considerable inroads in today's health. Genetic screening looks for alterations in genes, proteins and small molecules related to hereditary disorders. The publicly funded GeneTests Web site lists 598 laboratories testing for 1,265 diseases and conditions. Most tests are offered prenatally or to newborns, but tests for adult-onset conditions such as breast and colon cancer have become more widely available.

What Does It All Mean?

Patients are taking advantage of the explosion of new tests. Following an ad campaign for genetic testing for two breast cancer-related genes, genetic services referrals jumped by 200 percent at a large Colorado managed-care organization. Yet, people often don't know what tests deliver. A 2004 systematic review on prenatal and newborn genetic screening programs found that most women did not have enough information to make informed decisions.

Psychological Costs

Genetic screening carries costs beyond the monetary. Relatively little research exists on the psychological effects of screening, although "anxiety is clearly raised in women receiving positive screening results, especially young women," says Josephine Green, Ph.D., a reproductive health researcher at the University of York in England. Some people are worried about genetic discrimination: a 2003 survey about colon cancer risks conducted in a black population found that a third of those surveyed were worried genetic testing could lead to discrimination.

The Facts:

• New parents received misleading information from pediatrics residents about their newborn’s genetic screening testing in 41 of 59 conversations analyzed by researchers in a 2005 study. ⁵

• A 2005 pediatrician study found the doctors’ willingness to include more medical conditions in newborn screenings correlated with their willingness to test their own children for these conditions, not with their professional judgment about the tests’ value. ⁶

• A large Swedish study of newborn screening for type 1 diabetes found that mothers were more satisfied than fathers by the information on the disease and its risks provided by the screening. ⁷

• When health authorities in New England increased the number of newborn screening tests from 9 to 30 disorders, there was a 31 percent increase in the number of infants identified with a problem. ⁸

• A 2004 systematic review found no controlled studies about the best way to disclose to parents that their newborn is a genetic carrier for conditions such as sickle cell anemia or cystic fibrosis. ⁹

• If amniocentesis was routinely recommended for pregnant women age 35 and over, one in every seven pregnant women in the United States would undergo the procedure, according to a 2005 calculation. ¹⁰

• A 2005 systematic review of screening for inherited ovarian and breast cancer susceptibility in primary care concluded there is not enough evidence to evaluate the benefits and harms of this approach in the general population. ¹¹

• A 2005 literature review concludes that genetic testing does not increase psychological distress among breast cancer patients. ¹²

• A 2005 survey of black college freshman with favorable attitudes toward smoking found that those who believed they were at highest risk for developing lung cancer were the most interested in genetic screening for their susceptibility to the disease. ¹³

• While 83 percent of psychiatrists say it is part of their role to discuss genetic information with patients and their families, fewer than 25 percent say they are competent and prepared to do so, according to a 2005 survey. ¹⁴

• People who did 12 weeks of muscle training and were screened for a range of muscle genetic variations were more likely to attribute any training success to genetics if they received a “positive” screen. ¹⁵

Testing Kids for Adult Diseases

New parents routinely offer up newborns for a quick prick on the heel and a few droplets of blood to test for a variety of genetic disorders, and usually receive a clean bill of health. But some parents face a more complicated and often agonizing choice years later: Should they test their children for genetic conditions that may affect them as adults?

Genetic screening of children and teens for adult-onset conditions is still mostly confined to diseases that are inherited, fatal, with no potential cure and possibly appearing early in life, such as the neurological disorder Huntington’s disease. Dr. Edward McCabe, a genetic medicine specialist at UCLA, says most clinical organizations such as the American Academy of Pediatrics “have some general guidelines that say to screen children only if you can do something that would affect a child’s health before they come to the age of majority.”

In a 2005 international survey of pediatricians, most said they supported such screening guidelines. And yet many of the same physicians said they had sent children for adult-onset screening and even disclosed the results to “mature minors” 14 years or older. ¹⁶

“Screening for adult-onset disease is still a challenge,” even among adults, McCabe acknowledges. Little research exists on whether the health benefits of screening outweigh the potential psychological burden of testing positive for a disease, a burden that could fall heavily on both parents and child. Without genetic counseling, parents can be confused by what McCabe calls the “genotype/phenotype question,” where children can be genetic carriers of a disease but will not have the disease itself.

Some physicians have asked whether screening is ethical, since “there are very few of these disorders for which we have a magic bullet” that would cure or even alleviate symptoms, McCabe says.

“And once you pass the newborn nursery, there is no good venue to get 100 percent of the population screened,” which makes it hard to calculate the impact of young adult screening on public health, McCabe says.

Dr. Martin Delatycki, a professor at the Bruce Lefroy Centre for Genetic Health Research in Parkville, Australia, agrees that the rarity of child and teen genetic screening makes it difficult to systematically study its costs and benefits. Delatycki writes that “there is virtually no empirical evidence available” on the effects of such tests. ¹⁷

Still, the limits of screening don’t worry everyone. A 2005 study of college-age students found that most would undergo a genetic test that predicted their risk of developing the hereditary blood disease hemochromatosis. (18) McCabe says high-schoolers in a pilot program in Montreal are screened for Tay-Sachs disease and beta-thalassemia as part of their biology classes.

The demand has created new challenges “in educating the health care provider community about how you do genetic screening,” McCabe says. At UCLA, medical students now play the roles of parents and patients in mock genetic counseling sessions, “so they can really understand what it’s all about,” he says.

Expert Sources:

References

1. GeneTests Web site, summary statistics. Last accessed 05-17-06 at http://www.genetests.org.
   
   
2. J. Mouchawar et al. (2005) Assessing controversial direct-to-consumer advertising for hereditary breast cancer testing: reactions from women and their physicians in a managed care organization. American Journal of Managed Care, 11, 601-618.
   
   
3. J.M. Green et al. (2004) Psychosocial aspects of genetic screening of pregnant women and newborns: a systematic review. Health Technology Assessment, 8, 1-109.



4. J.A. Satia et al. (2006) Genetic testing for colon cancer among African-Americans in North Carolina. Preventive Medicine, 42, 51-59.
   
   
5. A. LaPean and M.H. Farrell (2005) Initially misleading communication of carrier results after newborn genetic screening. Pediatrics, 116, 1499-1505.
   
   
6. K. Acharya et al. (2005) Pediatricians' attitudes toward expanding newborn screening. Pediatrics, 116, e476-e484.
   
   
7. B. Lernmark et al. (2004) Parent responses to participation in genetic screening for diabetes risk. Pediatric Diabetes, 5, 174-181.
   
   
8. A.M. Comeau et al. (2004) Integration of new genetic diseases into statewide newborn screening: New England experience. American Journal of Medical Genetics. Part C, 125, 35-41.
   
   
9. S. Oliver et al. (2004) Disclosing to parents newborn carrier status identified by routine blood spot screening. The Cochrane Database of Systematic Reviews, 2004, Issue 4.
   
   
10. . R.G. Resta (2005) Changing demographics of advanced maternal age (AMA) and the impact on the predicted incidence of Down syndrome in the United States: Implications for prenatal screening and genetic counseling. American Journal of Medical Genetics Part A, 133, 31-36.
    
    
11. H.D. Nelson et al. (2005) Genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility: systematic evidence review for the U.S. Preventive Services Task Force. Annals of Internal Medicine, 143, 362-379.



12. K.J. Schlich-Bakker et al. (2005) A literature review of the psychological impact of genetic testing on breast cancer patients. Patient Education and Counseling, E-publication ahead of print, 17 Oct 2005.



13. C.M. McBride et al. (2005) Interest in testing for genetic susceptibility to lung cancer among Black college students "at risk" of becoming cigarette smokers. Cancer Epidemiology, Biomarkers and Prevention, 14, 2978-2981.



14. C.T. Finn et al (2005) Psychiatric genetics: a survey of psychiatrists' knowledge, opinions, and practice patterns. Journal of Clinical Psychiatry, 66, 821-830.



15. E.S. Gordon et al. (2005) Nondisease genetic testing: reporting of muscle SNPs shows effects on self-concept and health orientation scales. European Journal of Human Genetics, 13, 1047-1054.



16. R.E. Duncan et al. (2005) An international survey of predictive genetic testing in children for adult onset conditions. Genetics in Medicine, 7, 390-396.



17. R.E. Duncan and M.B. Delatycki (2006) Predictive genetic testing in young people for adult-onset conditions: where is the empirical evidence? Clinical Genetics, 69, 8-16.



18. B.L. Hicken et al. (2005) Perceptions and attitudes about HFE genotyping among college-age adults. Journal of Genetic Counseling, 14, 465-472.

The Center for the Advancement of Health identifies and disseminates state-of-the-science evidence about the influence of behavioral, social and economic factors on disease and well-being. Its purpose is to support health decision-making by the public and strengthen relationships among researchers and policymakers. The Center receives funding from a number of foundations, principally The Annenberg Foundation, the John D. and Catherine T. MacArthur Foundation and the W.K. Kellogg Foundation.

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