Interdisciplinary team approach to Tay-Sachs disease diagnosis and counseling

Genetic Disease Diagnosis

The Trosacks

Initial visit: three to five appropriate members for an interdisciplinary team

When the Trosacks come for their initial consultation, they must first seek to gain insight into the nature of Tay-Sachs disease, particularly because they are unfamiliar with the illness and do not know any family members who have coped with the disease. This revelation is new and entirely unexpected. A certified genetic counselor with a specific understanding of Tay-Sachs should be present to explain the disease's origin and transmission in layperson's terms.

Coping with the difficulties of a traumatic genetic diagnosis also requires a grief counselor with training in how to help parents cope psychologically with their new diagnosis. And finally, a doctor must be able to explain the full range of options for the Trosacks, spanning from termination to deciding to allow the pregnancy to progress.

Identify from whom you can obtain information for the Trosacks' initial visit

Before the Trosacks' initial visit, the nurse should consult with members of the treatment team to gain a full understanding of the disease, including its most 'common' expression (although all forms of Tay-Sachs are rare) and less common manifestations (such as adult onset Tay-Sachs). What is known and what is not known, medically speaking, should be clearly established. Talking with counselors about the psychological manifestations the Trosacks may exhibit, like the 'denial' stages of grief, as they relate to a terminal genetic diagnosis, is essential to better understand the Trosacks' likely reaction. The costs -- time and financial -- of treating a child with Tay-Sachs should also be broached.

Explain the type of information you expect to obtain from each member

A genetic counselor can specifically explain the genetic origins of the illness and the decisions that the Trosacks will face in the future, should they choose to conceive another child and the likelihood of that child manifesting Tay-Sachs or being a carrier of the disease. A doctor can prepare for the additional care that a child with Tay-Sachs will demand, both financially and in terms of the couple's time. Grief counselors can attend to the couple's needs, separate from questions pertaining to medical aspects of their case.

Part II: Teaching plan

Genetic diagnosis

One of the difficulties for the Trosacks to understand why the fetus Rita is carrying may have Tay-Sachs is the apparent absence of a genetic history of the illness. Tay-Sachs is associated with European Jewish ancestry. "The incidence of Tay-Sachs is particularly high among people of Eastern European and Ashkenazi Jewish descent" (NINDS Tay-Sachs Disease Information Page, 2011, NINDS).However, there are enough 'missing links' in terms of the couple's genetic history to suggest that they may have ties to the affected community. Additionally, it has been found to be prevalent in some "non-Jewish populations, including people of French-Canadian/Cajun heritage" as well as members of Amish communities (Tay-Sachs, 2011, Kids Health).

What is known of their grandparents indicates that Tay-Sachs very likely does run in the family. Rita's paternal grandparents had two children. One son died at an early age of unknown causes. Peter's paternal grandparents had three children, including a daughter and son who died young, of unknown causes. This was long before Tay-Sachs was well-known and before genetic screening was possible. When parents with a history of Tay-Sachs have a child there is a 50% likelihood that the child will be a carrier, but not manifest the disease, and a 25% likelihood that the child will not get the gene at all OR manifest full-blown Tay-Sachs (Tay-Sachs, 2011, Kids Health).

"Patients and carriers of Tay-Sachs disease can be identified by a simple blood test that measures beta-hexosaminidase A activity. Both parents must carry the mutated gene in order to have an affected child" (NINDS Tay-Sachs Disease Information Page, 2011, NINDS).

Treatment

The Trosacks must first understand the nature of the illness, and why it occurs. To an uninitiated observer, the disease seems very strange, because the baby with the disease will likely seem normal at birth. Tay-Sachs symptoms are caused by the build-up of a fatty substance called ganglioside GM2 in the tissues and nerve cells in the brain, due to "insufficient activity of an enzyme called beta-hexosaminidase A that catalyzes the biodegradation of acidic fatty materials known as gangliosides. Gangliosides are made and biodegraded rapidly in early life as the brain develops" (NINDS Tay-Sachs Disease Information Page, 2011, NINDS). As the nerve cells begin to swell with "fatty material, a relentless deterioration of mental and physical abilities occurs. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy and paralysis sets in. Other neurological symptoms include dementia, seizures, and an increased startle reflex to noise" (NINDS Tay-Sachs Disease Information Page, 2011, NINDS).

Unfortunately, there is no cure or effective treatment for Tay-Sachs. Children with the disorder usually die before the age of four. "Anticonvulsant medicine may initially control seizures. Other supportive treatment includes proper nutrition and hydration and techniques to keep the airway open. Children may eventually need a feeding tube" (NINDS Tay-Sachs Disease Information Page, 2011, NINDS).

Prognosis as it applies to Tay-Sachs

The prognosis for Tay-Sachs can be described as grim, due to the inevitable progression of the illness. In rare forms of the disease, a child may have the Hex A enzyme, "but not enough of it to prevent developmental problems," which slows the progression of the illness (Tay-Sachs, 2011, Kids Health). Symptoms may not manifest until the child is a toddler, "but death usually occurs by the time the child is 15 years old" (Tay-Sachs, 2011, Kids Health). "In another, milder form of Tay-Sachs, the disease causes muscle weakness and slurred speech, but sight, hearing, and mental capabilities remain intact" (Tay-Sachs, 2011, Kids Health). However, this form of the disease is very rare.

Support groups and appropriate referrals

Given that "The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), conducts research about Tay-Sachs disease in laboratories at the NIH and also supports additional research through grants to major medical institutions across the country," if the Trosacks wish to continue the pregnancy, they may wish to become a part of a clinical trial, to advance current knowledge about the illness NINDS Tay-Sachs Disease Information Page, 2011, NINDS). Finding links to a support group is also important, particularly since the Trosacks have no ties to a community where the disease is well-known.

Pregnancy information

For the expectant mother, her experience of pregnancy will be 'normal' and there are no precautions she can take, other than termination to prevent the child's illness from taking its natural course.

Part III

Three ethical implications regarding the availability of personal genetic information

One of the greatest concerns about the availability of personal genetic information is that it might be used to deny coverage to relevant parties, despite legal restrictions upon the disclosure of private health information. Because children with genetic disorders are likely to be more expensive to treat, it is often feared that demonstrated genetic markers for manifesting a particular medical illness may result in a denial of coverage. If the Trosacks decide to have another child, they may fear their genetic diagnosis, if known, could also make it difficult for them to secure affordable insurance. However, "the Genetic Information Nondiscrimination Act of 2008, also referred to as GINA, is a new federal law that protects Americans from being treated unfairly because of differences in their DNA that may affect their health" (Genetic discrimination fact sheet, 2011, Genome.gov)

The second concern is the ability of parents to fully process information regarding genetic disorders. Particularly in instances like the Trosacks, where there is already a wanted pregnancy, parents are faced with the decision to either abort the pregnancy and try again to have a fetus that may not have the disorder, or to have a child which will suffer from a genetic disorder that is likely to be both painful and fatal. Communicating the likely implications of both choices requires sensitivity on the part of the counselor to the parents' religious beliefs. The parents must fully understand the nature of their decision to make an intelligent and informed choice.

There is also the third, final difficulty of what may transpire if the parents are conflicted about what to do, and how to help the couple reach a decision together. Currently, the Trosacks say they have a religious objection to abortion, but given the situation, it is not unusual for a couple to disagree as they come to a final consensus. The counselor should not take sides, however he or she should strive to mediate between both husband and wife to ensure they are communicating their feelings in an open and accurate manner.