Case and Commentary
Sep 2009

Presymptomatic Testing of Children for Huntington's Disease, Commentary 3

Leon Dure, MD
Virtual Mentor. 2009;11(9):668-672. doi: 10.1001/virtualmentor.2009.11.9.ccas2-0909.


Dr. Carpenter had taken care of 3-year-old Josh since he was born. One afternoon, Dr. Carpenter received a call from Josh’s parents, both of whom were successful professionals. Josh’s dad had just been diagnosed with Huntington’s disease, a degenerative, neurological disorder, and the parents wanted Josh to be tested for the disease. The genetic polymorphism for Huntington’s is autosomal dominant, so Josh had a 50-50 chance of inheriting the gene from his father, and, if he did, he would develop the disease if he lived to middle age.

After offering her condolences to Josh’s parents, Dr. Carpenter expressed what she considered to be a consensus opinion on the matter: “At present, there is no prevention, treatment, or lifestyle change that has an effect on expression of the gene. For these reasons, pediatric and genetic medicine specialty societies advise against testing children. Josh will have plenty of time to decide whether he wants to be tested once he is an adult.”

“I disagree completely,” said Josh’s mom. “If Josh grows up knowing he has this condition, he will be much better prepared to deal with it as an adult. He’ll be forming his identity over the next 18 years. Assuming he has the disease, he won’t face the trauma of having his identity and life plan change all at once.”

“But you’ll be denying him the chance to make the decision as an adult,” replied Dr. Carpenter. “Maybe he will decide not to know.”

“Isn’t that what parents do?” said Josh’s dad. “They make decisions for their children. If we take your approach, Josh may be 25 when he discovers that he wishes he knew all along whether or not he has Huntington’s. But he won’t have that option because of our decision not to test him. The choice to do nothing is still a choice, Dr. Carpenter.”

Commentary 3

This clinical case is particularly relevant for at least two reasons. First, the development of greater awareness of genetic testing for specific diseases by the public requires that clinical care professionals be knowledgeable not only about the types and meanings of tests, but also of the consequences of obtaining such tests. Secondly, there are significant ethical issues that are brought to light by this case, especially as they relate to genetic testing of minor children.

Physician’s Perspective

Dr. Carpenter is essentially correct with respect to her interpretation of professional guidelines for testing of minor children at risk for Huntington’s disease (HD). Both lay and professional organizations in the United States, Canada, and Europe recommend that testing of asymptomatic children await an age at which the child’s consent can be reliably given [1-3]. Justification for this policy comes from the fact that there is no cure, nor are there any proven lifestyle modifications or treatments that can delay or alter the onset and course of the condition. Thus, from a health care professional’s perspective, it can be argued there is no medical reason for obtaining the test. This does not imply that testing may only be offered when a child meets an “official” age of consent, depending on a state or country’s definition, but at the very least it indicates a preference that children exhibit some understanding of the test and its consequences. An emancipated minor, for example, could undergo testing. An important distinction is made in the case of symptomatic testing—a child with clinical symptoms of early-onset or juvenile HD. Here, testing is often entertained as a means of identifying a particular diagnosis and avoiding further invasive or intrusive tests. In this case of a healthy 3-year-old, however, such reasoning does not apply.

Another point from Dr. Carpenter’s perspective is the identification of Josh as the patient. Practicing physicians who care for children rely on parents to collaborate on decisions relating to health care. Tensions can arise, however, when parents’ motivations or decisions are at odds with those of a child’s caregivers. Such conflicts commonly occur in the context of scheduled vaccinations in childhood, and parent-driven requests for genetic testing may develop into a similar problem. Despite these potential areas of disagreement, physicians must acknowledge their duty to a patient and act accordingly.

Parental Perspective

The parental viewpoint touches on ethical issues that are unique to medical care of children. Parents are considered surrogate decision makers for their children, as minors are for the most part considered unable to make independent health care decisions [4]. It must be noted that children are distinct from other populations with impaired decision-making capacity, notably individuals who, by virtue of an injury or condition occurring early in life, will never develop competence and individuals who may have lost the ability to make decisions through injury, aging, or disease. Children, on the other hand, are considered “precompetent,” in that they are expected to develop the resources and capabilities to make independent health care decisions. As a general concept, the goal of health care decision making is to ensure an open future for children by preserving as many options as possible for the time when they develop into competent individuals and members of society.

In this case, the parents state their conviction that, should Josh test positive for Huntington’s disease now, he would be better prepared and have more time to accept the diagnosis. Moreover, the parents assert that they know best and have the right to make decisions for Josh. The conflict pits parental autonomy against the potential threat that testing for HD could have on a child’s open future.

Prevailing Views

Most professional organizations argue that testing for Huntington’s disease and the determination of a positive test (meaning possession of the mutation for HD) would imperil the open future that is the ideal for a child. Consequences of a child’s testing positive for HD could include stigmatization, discrimination, damage to self-esteem, and perhaps limitations on educational and other pursuits that might be enjoyed by any other individual.

Because specific data on children is sparse, it is informative to consider how adults have responded to genetic testing for HD. Overall, it is estimated that only 10 to 20 percent of at-risk individuals undertake presymptomatic testing for HD, despite availability of the test since the mid-1990s. Adults have reported a number of concerns about the consequences of testing, ranging from obvious fears of discrimination by insurers to less-tangible concerns regarding how testing could be communicated to other family members [5, 6]. Interestingly, the issues of communication arise regardless of the test results. The fact that a minority of eligible adults undergoes genetic testing despite ready access suggests that any particular child would have a fairly high likelihood of refusing testing after attaining adulthood. Testing a child would thus restrict choices that would be available in adulthood.

Critics of this view point out that there is little evidence to substantiate these concerns [7]. Moreover, they argue that testing of a minor child has a 50 percent chance of indicating no risk of HD and that withholding such information could have deleterious effects. As is true of the converse, this contention suffers from minimal supportive evidence, leaving health care professionals to navigate the course themselves. One approach has been to consider the best-interest standard, a construct that is very much in line with the societal goal of providing an open future to children [8]. When this standard is applied to the issue of childhood testing for HD, it is clear that, by refusing to test, the clinical community is exercising a duty to foster a best interest. Parents acting as surrogate decision makers for children also may have the same motives. Given the general acceptance of professional guidelines, though, it is apparent that physicians who care for children consider the risks of HD testing to outweigh potential benefit.

Clinician’s Response

So, what should Dr. Carpenter do? A compromise approach would be to investigate how the family is coping with the father’s new diagnosis of HD. Dr. Carpenter should attempt to understand each parent’s perspective of genetic testing and determine whether there is any particular conflict between their views. It would be important to establish whether the family plans to tell Josh, and when. Even critics of professional guidelines have indicated that the reason for testing is to have an open exchange of information and to share this information with the child and other family members. Given that Josh is a toddler, every effort should be made to convince the family that testing should be done when he is more mature.

Finally, it must be noted that many of the concepts and ideas regarding childhood testing for HD derive from the fact that there is little data relating to the attitudes of testing in childhood, nor is much known about how families typically tell their children about the disease. There is some evidence that people who have been tested while still minors have experienced both negative and positive consequences, but available data is not without controversy [9-11]. Research has only recently examined patterns of information transmission in families [12]. With respect to risk of HD, these data indicate that children are not informed early on about their own risk of disease and are typically not given such information until the second decade. Therefore, Dr. Carpenter should work to educate Josh’s parents about developing a long-term plan regarding how they could approach genetic testing, emphasizing the reasons for a judicious approach. Much of the basis for a disinclination to test is that HD has no cure and no effective treatment. If, on the other hand, a rational treatment strategy is developed for HD, the balance of arguments for and against testing will change dramatically.

This case illustrates a number of significant tensions not only within the medical community but also between physicians and parents of minor children. A final word to the reader: physicians must be clear that, in this case, the child is the patient, and a best-interest standard may be in conflict with parental wishes.


  1. Clarke A; Working Party of the Clinical Genetics Society (UK). The genetic testing of children. J Med Genet. 1994;31(10):785-797.

  2. Tassicker RJ, Marshall PK, Liebeck TA, Keville MA, Singaram BM, Richards FH. Predictive and pre-natal testing for Huntington Disease in Australia: results and challenges encountered during a 10-year period (1994-2003). Clin Genet. 2006;70(6):480-489.
  3. Wertz DC, Reilly PR. Laboratory policies and practices for the genetic testing of children: a survey of the Helix network. Am J Hum Genet. 1997;61(5):1163-1168.
  4. Miller RB. Children, Ethics, and Modern Medicine. Bloomington, IN: Indiana University Press; 2003.

  5. Almqvist EW, Brinkman RR, Wiggins S, Hayden MR; Canadian Collaborative Study of Predictive Testing. Psychological consequences and predictors of adverse events in the first 5 years after predictive testing for Huntington’s disease. Clin Genet. 2003;64(4):300-309.

  6. Klitzman R, Thorne D, Williamson J, Chung W, Marder K. Disclosures of Huntington disease risk within families: patterns of decision-making and implications. Am J Med Genet A. 2007;143A(16):1835-1849.

  7. Sevick MA, Nativio DG, McConnell T. Genetic testing of children for late onset disease. Camb Q Healthc Ethics. 2005;14(1):47-56.
  8. Kopelman LM. Using the best interests standard to decide whether to test children for untreatable, late-onset genetic diseases. J Med Philos. 2007;32(4):375-394.
  9. Duncan RE, Gillam L, Savulescu J, Williamson R, Rogers JG, Delatycki MB. “Holding your breath”: interviews with young people who have undergone predictive genetic testing for Huntington disease. Am J Med Genet A. 2007;143A(17):1984-1989.
  10. Duncan RE, Gillam L, Savulescu J, Williamson R, Rogers JG, Delatycki MB. “You’re one of us now”: young people describe their experiences of predictive genetic testing for Huntington disease (HD) and familial adenomatous polyposis (FAP). Am J Med Genet C Semin Med Genet. 2008;148C(1):47-55.

  11. Richards FH. Predictive genetic testing of adolescents for Huntington disease: a question of autonomy and harm. Am J Med Genet A. 2008;146A(18):2443-2448.
  12. Dure LS, Quaid K, Beasley TM. A pilot assessment of parental practices and attitudes regarding risk disclosure and clinical research involving children in Huntington disease families. Genet Med. 2008;10(11):811-819.


Virtual Mentor. 2009;11(9):668-672.



The people and events in this case are fictional. Resemblance to real events or to names of people, living or dead, is entirely coincidental. The viewpoints expressed on this site are those of the authors and do not necessarily reflect the views and policies of the AMA.