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Pediatric Otolaryngologists' Knowledge and Understanding of Genetic Testing for Deafness
Nathaniel H. Robin, MD;
Christin Dietz;
James E. Arnold, MD;
Richard J. H. Smith, MD
Arch Otolaryngol Head Neck Surg. 2001;127:937-940.
ABSTRACT
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Objective To assess the level of a cohort of pediatric otolaryngologists' knowledge
and understanding of genetics and genetic testing for deafness and hard of
hearing (D/HOH).
Methods A questionnaire was designed to assess the level of knowledge and understanding
of the genetic basis and genetic testing for deafness among a cohort of pediatric
otolaryngologists. Three hundred questionnaires were made available to attendees
of the 14th (1999) Annual Meeting of the American Society of Pediatric Otolaryngology,
Palm Desert, Calif. A series of questions asked to gauge the respondent's
level of knowledge of genetics and hearing impairment addressed estimating
recurrence risks for deaf and normal-hearing parents and the likelihood of
detecting a mutation in connexin 26 in specific clinical scenarios.
Results A total of 28 questionnaires were completed and returned. All respondents
reported that they regularly saw patients for D/HOH. Almost half commonly
refer these patients for genetic testing and counseling. Seventeen (71%) of
24 otolaryngologists stated they offered genetic testing in all situations,
while 6 offered counseling only at parental request or to address recurrence
risk issues. One otolaryngologist offered genetic testing if there was a deaf
sibling. Twelve (67%) of 18 offered pretest counseling, which was most frequently
provided by a genetic counselor. Although 3 (19%) of 16 otolaryngologists
provided the counseling themselves, 2 (13%) reported that they and a genetic
counselor provided the counseling. While 24 (89%) of the 27 correctly stated
that nonsyndromic D/HOH is usually autosomal recessive, recurrence risks were
incorrectly estimated in several examples.
Conclusions While the surveyed pediatric otolaryngologists have a good knowledge
of genetics and genetic testing for D/HOH, recurrence risks were often inaccurate.
Since D/HOH testing is clinically available, it is imperative that physicians
are educated about genetics and genetic testing and are able to communicate
this to their patients and their patients' families.
INTRODUCTION
WE ARE entering a new era in the diagnosis and management of deafness
and hard of hearing (D/HOH), as genetic testing is becoming an integral part
of the evaluation of these affected patients.1-2
In previous work, we have shown that normal-hearing parents of deaf children
have a positive attitude toward genetic testing for deafness and recognize
the benefits of such testing.3 However, an
unexpected finding was the parents' lack of understanding of the genetics
of their child's deafness even after genetic testing had been completed. Parents
who had had genetic testing for their deaf child were just as likely to have
a poor understanding of the recurrence risk of their having another deaf child
as those who had not had such testing. Almost all respondents (28/29, 97%)
had a poor understanding of their chance to have another deaf child, usually
underestimating their recurrence risk at 0%. Parents also failed to understand
their child's recurrence risk. These finding suggested that the testing group
h d not received genetic counseling or that the counseling was inadequate.
Because many families of deaf children interact with pediatric otolaryngologists,
we conducted a pilot study of these physicians to assess their level of knowledge
and understanding of genetics and genetic testing.
PARTICIPANTS AND METHODS
Participants for this study were recruited at the 14th (1999) Annual
Meeting of the American Society of Pediatric Otolaryngology, Palm Desert,
Calif. A packet that contained a brief explanatory letter, a questionnaire,
and a self-addressed stamped envelope was made available to all attendees
of this meeting. There were no inclusionary or exclusionary criteria. The
study received approval by the institutional review board of University Hospitals
of Cleveland, Cleveland, Ohio, but since the questionnaires were anonymous,
signed informed consent was not needed. The 3 areas of focus were demographics,
practice policies regarding pediatric hearing impairment, and general knowledge
of the genetics of hearing impairment.
RESULTS
More than 300 questionnaires were made available at the meeting, but
only 28 were completed and returned. Because the questionnaire packet was
made available and not specifically mailed to individuals, it is impossible
to give a response rate; however, given the small sample size, the significance
of these results is not definitive, but rather represents pilot data. The
results of the questionnaire are given in the Table 1.
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Selected Results of the Questionnaire*
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Most respondents completed their otolaryngology training in the 1980s
or 1990s (22/28, 80%), with 96% (27 respondents) training at a university-based
hospital. Twenty (71%) of 28 had some fellowship training, with 12 (60%) of
the 20 having had a 1-year pediatric fellowship, and 6 (30%) of the 20 having
had a 2-year fellowship. More than half (21/28, 75%) responded that they are
in an academic practice, and an additional 3 (11%) of the 28 were affiliated
with an academic medical center; 4 respondents (14%) were in private practice.
All reported that they regularly saw patients for D/HOH. Almost half
the respondents (13/27, 48%) stated that they would refer these patients for
genetic testing and counseling. When asked under what conditions they offer
genetic testing, 17 (71%) of 24 otolaryngologists stated in all situations,
while 6 (25%) offered counseling only at parental request or to address recurrence
risk issues. Twelve (67%) of 18 offered pretest counseling. Counseling was
most frequently provided by a genetic counselor, although some otolaryngologists
provided the counseling themselves (3/16, 19%) or together with a genetic
counselor (2/16, 13%).
The series of questions intended to gauge the respondent's level of
knowledge of genetics and hearing impairment addressed estimating recurrence
risks for deaf and normal-hearing parents, and the likelihood of detecting
a mutation in connexin 26 in specific clinical scenarios. Although almost
all respondents (25/28, 89%) stated that most nonsyndromic D/HOH is autosomal
recessive, recurrence risks were incorrectly estimated in several cases. For
example, when asked what the chance is for 2 deaf parents to have a deaf child,
the most common answer (10/27, 37%) was 10%, which is correct, but 18 (67%)
responded incorrectly, with 15 (56%) of the 27 giving recurrence risks from
25% to 100%. The most common recurrence risk estimate given for normal-hearing
parents of a deaf child was 25% (15/28), with only 43% (12/28) giving the
correct estimate (10%-18%).
Most knew that approximately one third of the deaf children born to
normal-hearing parents test positive for a Cx26 gene
mutation, but most did not recognize that two thirds of normal-hearing siblings
of such children are carriers of a Cx26 mutation.
All (28) stated that they would be willing to test the normal-hearing sibs
of the Cx26-positive deaf child at the parents' request.
COMMENT
The results of this pilot study suggest that the surveyed pediatric
otolaryngologists have a good knowledge of genetics and genetic testing for
D/HOH. For example, most knew that the majority of isolated D/HOH was due
to genetic factors and that most pediatric cases were autosomal recessive.
Most (4 of 28 respondents) correctly stated that a deaf child born to normal-hearing
parents would have an approximately 33% chance of having a Cx26 gene mutation detected. However, one disconcerting issue was the
inaccurate perceptions of recurrence risks in specific situations. Most respondents
overestimated recurrence risk in the 2 given situations (2 deaf parents or
2 normal-hearing parents with 1 deaf child, Table 1). Because, as this study suggests, many pediatric otolaryngologists
are using genetic testing for D/HOH, it is important ensure that parents and
patients receive correct and accurate information relating to these issues.
As many studies have shown, pretest genetic counseling is necessary if the
parents and patients are to receive the maximum benefits from genetic testing.4 With pretest and posttest counseling, parents and
patients have a greater understanding of their test results—both the
meaning and limitations of the findings. For example, Brunger et al have reported
that parents of deaf children who test negative for Cx26 deafness often mistakenly believe that their deaf child does "not
have the deafness gene."3(p1623) These parents
were either never told or did not understand that this test screens only one
of dozens of genes that can cause deafness. Thus, instead of a very low recurrence
risk, normal-hearing parents of a deaf child who tests negative for Cx26 mutations still have a recurrence risk of approximately
14% (R.H.J., unpublished data, 1999).
Another interesting point is that all respondents stated that they would
agree to test the normal sibs of a child with Cx26-related
deafness. While there is a 67% chance that each sib would be a carrier, current
recommendations are that carrier testing of children for genetic disease should
not be done. It is reasoned that carrier testing provides no medical benefit
to a child and is only important for reproductive decision making. Such decisions
will be made years later, when the child is an adult. As an adult, the child
(as an adult making reproductive decisions) has the right not to know their
carrier status if they so choose. Therefore, it is believed that decisions
concerning carrier testing for genetic disease should, in general, be left
to the child as an adult, not their parents.5
CONCLUSIONS
We are entering an age in which genetic testing is becoming more common
and widely used, and studies such as this one emphasize the need for continuing
education and the value of genetic counseling in an effort to maximize benefits
to patients. However, we are not suggesting that every patient undergoing
genetic testing for D/HOH needs to be seen by a geneticist or genetic counselor.
Rather, it is anticipated that this pretest and posttest genetic counseling
will be done by the primary physician, the pediatrician, or the otolaryngologist,
with genetics becoming involved in only difficult or atypical cases. But it
is imperative, therefore, that the counseling be provided in the recommended
manner, by knowledgeable providers and with adequate time allotted for questions
and gaining feedback.6
AUTHOR INFORMATION
Accepted for publication February 7, 2001.
Corresponding author: Nathaniel H. Robin, MD, Lakeside 1500, Cleveland,
OH 44106-6506 (e-mail: nhr2{at}po.cwru.edu).
From the Departments of Genetics (Dr Robin and Ms Dietz), Pediatrics
(Drs Robin and Arnold), Otolaryngology and Head and Neck Surgery (Drs Robin
and Arnold), and Reproductive Biology (Dr Robin), Case Western Reserve University
School of Medicine, University Hospitals of Cleveland, Cleveland, Ohio; and
the Department of Otolaryngology and Head and Neck Surgery and the Interdepartmental
Genetics PhD Program, University of Iowa, Iowa City (Dr Smith).
REFERENCES
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1. Cohn ES, Kelley PM, Fowler TW, et al. Clinical studies of families with hearing loss attributable to mutations
in the connexin 26 gene. Pediatrics. 1999;103:546-550.
FREE FULL TEXT
2. Van Camp G, Smith R. Hereditary hearing loss home page. Available at: http://www.uia.ac.be/dnalab/hhh. Accessed
September 7, 2000.
3. Brunger JW, Murray GS, O'Riordan MA, Matthews AL, Smith RJH, Robin NH. Parental attitudes toward genetic testing for pediatric deafness. Am J Hum Genet. In press.
4. Brunger JW, Matthews AL, Smith RJH, Robin NH. Genetic testing and genetic counseling for deafness: the future is
here. Laryngoscope. In press.
5. Beauchamp TL, Childress JS. Genetic testing for children and adolescents: who decides? In: Principles of Biomedical Ethics. 4th
ed. New York, NY: Oxford University Press; 1994:142-181.
6. Chappel A, May C, Campion P. Lay understanding of genetic disease: a British study of families attending
a genetic counseling serviuce. J Genet Couns. 1995;4:281-300.
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