Term Paper: Genetic Counseling and Retinoblastoma
Tristan Lawson
BIOL 303-501
Dr. Bert Ely
November 5, 2010
Retinoblastoma is the most common intraocular malignancy in children and
originates in the cells of the retina. About 1 in every 15,000 to 20,000 births
involves a child with retinoblastoma. Retinoblastoma develops rapidly and can
cause blindness if not corrected quickly. Luckily, about 9 out of every 10 cases is
cured through treatment options such as cryotherapy, chemotherapy, laser surgery,
and radiation therapy. However, some of the treatments for the cancer can cause
serious side effects such as vision problems. Also, children with retinoblastoma are
more likely to develop secondary cancers. Retinoblastoma can be unilateral,
bilateral, or in rare cases trilateral where it affects both eyes and the pineal gland.
The cause of retinoblastoma can either be genetic or non-genetic. Genetic
retinoblastoma is caused by a mutation on chromosome 13 and is more likely to be
bilateral. Non-genetic retinoblastoma is caused by a random copy mistake during
cell division in early fetal development. Because retinoblastoma is a fairly common
genetic disorder with lasting effects, several studies have been done that investigate
the physical or psychological limitations that retinoblastoma leads to and the role of
genetic counseling in regards to retinoblastoma and decision making (Dommeringa
et al., 2010).
The decision by the parents to be tested to see if they are carriers or have a
child who may be at risk tested is very important. However, different factors
influence whether the parents utilize these testing services. In the study “RB1
genetic testing as a clinical service,” this decision is examined (Cohen et al., 2010).
Families in the U.S. who had RB1 testing done in Boston were sent a survey asking
them why they made their decision and how they interpreted the results. According
to this survey, 98% of respondents were strongly influenced by their physician to
undergo the testing. This result shows that physicians have a huge influence over
their patients and should be informing them of available and prudent options.
Another interesting aspect of this study was that most respondents correctly stated
their results, but one mother stated that her child’s results were negative when they
were actually positive (Cohen et al., 2010). Physicians and genetics counselors need
to be absolutely certain that their patients understand the results. Also, the study
revealed that patients who sought RB1 testing were well educated and in a middle
to high socioeconomic class (Cohen et al., 2010), suggesting that less educated and
poorer families are not able to afford or are not as aware of testing options. Care
must be taken in the future to ensure that all children are given equal access to
testing options.
Reproductive decisions are very complicated for couples where one or both
of the prospective parents are affected by retinoblastoma. Also, if neither parent
has retinoblastoma but a previous child has retinoblastoma, the decision is even
more complicated and emotional. Genetic counseling is the process where a genetic
counselor explains the risks, complications, and probability of a heritable disorder
in order to help couples with retinoblastoma as well as helping people with
retinoblastoma deal with their disease. The study “Reproductive decision-making: a
qualitative study among couples at increased risk of having a child with
retinoblastoma” gauged how couples perceived the risk of passing on
retinoblastoma to their children (Dommeringa et al., 2010). Couples interpreted the
statistical probability of passing on a genetic disorder based on their personal
experiences. If a couple had already had an affected child, the couple’s perceived
risk was generally higher than the statistical probability. Likewise, couples that had
not experienced the surgeries and screenings that accompany a child with
retinoblastoma perceived their risks as lower than the actual probability. Also,
when couples were making their decisions they tended to think of the child’s social
life and the burden of the disease on the child and on the family as very important
factors. Each couple made their own decision for different reasons, but a large
majority of couples that participated in genetic counseling found it to be helpful
(Dommeringa et al., 2010).
In another study, an additional aspect of reproductive decision-making after
genetic counseling was discussed (Kelley, 2009). This study analyzed the different
decisions that couples make and focused on the choice of not choosing to do
anything. Some couples that are confronted with an array of prenatal testing
opportunities and options simply choose to do nothing and let nature take its
course. Couples may limit tests to information only purposes, decline prenatal
testing for subsequent pregnancies, or avoid future pregnancies through
sterilization and other methods. In this particular study, in depth interviews were
conducted during a three-year span in the rural U.S. after genetic counseling
services were provided. The results showed that the choice not to take any action
was selected due to lack of understanding of the options available, lack of education,
a moral stance against abortion, and the feeling of being overwhelmed (Kelley,
2009). This study illustrates that genetic counseling can lead to different decisions,
but certain population groups will select certain decisions more often.
Another aspect of genetic counseling in regards to retinoblastoma is talking
to survivors of retinoblastoma about the physical and psychological affects that the
disease has had on their daily lives. This information is important not only to help
the person struggling with the aftermath of retinoblastoma, but also to help future
parents in reproductive decision-making by providing real life experiences. A study
called “Restrictions in daily life after retinoblastoma from the perspective of
survivors” focused on the perceived limitations of retinoblastoma and revealed
some common trends (Van Dijk, 2009). About 55% of survivors felt that
retinoblastoma had limited their lives in some way, either physically or emotionally.
The most common complaint was vision impairment and depth perception. As the
survivors aged, many experienced increased anxiety due to the possibility of
developing a secondary tumor or passing the disease to future offspring. Another
worrying trend that this particular study revealed was that 37% of survivors did not
attend mainstream education, and 39% of survivors experienced learning
difficulties at school related to vision or anxiety. Also, the average level of education
achieved by survivors was much lower than the average level of education achieved
by the general population. Around 47% of survivors also said that they were to
some degree restricted in participation in sports (Van Dijk, 2009). The various
statistics that this study compiled highlights that a disease is not only about life or
death, it is about the quality of life. When children are made fun of for looking
different, having learning disabilities, or not being as proficient at sports, it can have
a negative impact on their lives and their futures. These factors must be taken into
consideration when discussing topics such as reproductive decisions and other
elements of genetic counseling.
A developing area that genetic counseling is entering involves the new
techniques of prenatal diagnosis. In prenatal diagnosis, tests are performed to
determine if the fetus is affected by retinoblastoma. The parents can then decide to
terminate or sustain the pregnancy. Several different issues come into play when
talking about prenatal diagnosis. Many people are opposed to abortion because of
moral beliefs and refuse prenatal diagnosis because the result would be irrelevant.
Another issue is that some of the techniques such as chorion villi sampling are
invasive techniques that can cause miscarriages and infections (Dommeringa et al.,
2010). In one study, 2 couples out of the 14 participants chose to undergo prenatal
diagnosis. One of the couples had a 50% chance of passing on the Rb1 gene and
another had a 2% chance. The couple with the 2% chance chose to have the
procedure done because they were not able to deal with another child with
retinoblastoma because they were too involved with the treatment of their first
affected child. Another couple in the same study chose not to undergo the
procedure because they felt that choosing to sustain or abort a pregnancy was
wrong, and they felt that you should be happy with the child that you get no matter
what (Dommeringa et al., 2010). As prenatal diagnosis technologies develop and
become safer, more and more people will need help in deciding whether to have
these procedures done and how to interpret the results. For this reason, genetic
counseling will play an important role in this area.
Retinoblastoma and other genetic diseases are very much intertwined with
genetic counseling. Genetic counseling aids couples in reproductive decisions as
well as counseling survivors about the affects and limitations of their disease.
Genetic counseling will also incorporate prenatal diagnosis more as the procedures
become better known. Genetic counselors should learn to present more than
statistics to couples. They need to understand the human element of the disease
and the everyday problems that affected children will have to face. They need to
empathize with their patients in order to help them make the best decision for their
family. Genetic counseling is an extremely important asset for many people and the
roles of genetic counselors should continue to expand.
Works Cited
Cohen, Jennifer G., Thaddeus P. Dryja, Katherine B. Davis, Lisa R. Diller, and Frederick
P. Li. "RB1 Genetic Testing as a Clinical Service: A Follow-up Study." Medical
and Pediatric Oncology 37.4 (2001): 372-78. Web. 4 Nov. 2010.
Dommeringa, C. J., M. R. Van Den Heuvela, A. C. Molb, S. M. Imhofc, H. MeijersHeijboera, and L. Henneman. "Reproductive Decision-making: a Qualitative
Study among Couples at Increased Risk of Having a Child with Retinoblastoma."
Clinical Genetics 78 (2010): 334-41. Web. 4 Nov. 2010.
Isidro, Marichelle A. "Retinoblastoma: EMedicine Ophthalmology." EMedicine Medical Reference. 21 Sept. 2010. Web. 04 Nov. 2010.
<http://emedicine.medscape.com/article/1222849-overview>.
Kelly, Susan E. "Choosing Not to Choose: Reproductive Responses of Parents of
Children with Genetic Conditions or Impairments." Sociology of Health & Illness
31.1 (2009): 81-97. Web. 4 Nov. 2010.
Moll, A. C., D. J. Kuik, L. M. Bouter, W. Den Otter, P. D. Bezemer, J. W. Koten, S. M.
Imhof, B. P. Kuyt, and K. E W P. Tan. "Incidence and Survival of Retinoblastoma
in the Netherlands: a Register Based Study 1862-1995." British Journal of
Ophthalmology 81.7 (1997): 559-62. Web. 4 Nov. 2010.
Van Dijk, Jennifer, Kim J. Oostrom, Jaap Huisman, Annette C. Moll, Peggy T. CohenKettenis, Peter J. Ringens, and Saskia M. Imhof. "Restrictions in Daily Life after
Retinoblastoma from the Perspective of the Survivors." Pediatric Blood & Cancer
54 (2009): 110-15. Web. 4 Nov. 2010.