Case Study 1 - Thalassaemia
This case study presents the problems faced by a young couple who discover that they are both carriers of a serious genetic condition. In particular it looks at the dilemmas to be dealt with in relation to starting a family and impact of their genetic carrier status on reproductive decisions.
To demonstrate understanding of the ethical issues arising in relation to 'genetic carrier status': autonomy, informed consent, risk assessment, individual responsibility, ethical status of the early embryo, ethical status of the foetus, ethical problems associated with 'double effect' situations, human rights.
Assessment of Learning Outcomes: Completion of the questionnaire with a brief written reasoning accompanying each answer.
Teaching Structure/Format: Case study and questionnaire is handed out prior to a teaching session. Students read the case study prior to the session, discuss the issues during the session and complete the questionnaire after the session.
Thalassaemia is a genetic disease in which one of the main forms of globin is not synthesised. This in turn means that haemoglobin is not properly formed and the oxygen-carrying capacity of the blood is very severely compromised. Symptoms are first detected in the first few weeks after birth and becoming increasingly severe, leading to death. Treatment consists of frequent blood transfusions. Even then, life is very restricted. Any form of exercise is difficult, if not impossible and patients suffer chronic pain in joints and muscles. The frequent transfusions lead to an iron overload with which the kidneys are not able to cope. Most sufferers of thalassaemia die in their late teens or early twenties.
Eleni and Costas are a young married couple who wish to start a family. Their family histories indicate that they are at risk from carrying the thalassaemia mutation. A test is available at the local teaching hospital.
Should they take the genetic test? Why?
The tests show that they are both carriers of the condition. This means that each child conceived has a 1 in 4 chance of having thalassaemia, a 1 in 2 chance of being a carrier and a 1 in 4 chance of having two 'normal' gene copies. Eleni and Costas are concerned about the short odds. The doctor advises them that a foetus can be tested at about 14 weeks of pregnancy and if it is thalassaemic, the pregnancy can be terminated.
Is this an appropriate option for the couple? Why?
Eleni and Costas decide that they do not wish to consider termination of pregnancy but they are still concerned about the possibility of giving birth to a sick baby. The doctor further advises them: It is possible to have a baby via in vitro fertilisation (IVF). Several embryos will be created and will be tested at the eight-cell stage for the mutation. This is called pre-implantation genetic diagnosis (PGD). Thalassaemic embryos would be discarded. However, it is not possible to eliminate all carrier embryos: the need to implant three embryos means that it is statistically unlikely to obtain enough embryos for implantation that are completely free from the mutation.
Is PGD a more ethically acceptable option than termination of pregnancy? Why?
The couple decide to opt for IVF and PGD and are delighted when, after just one cycle of IVF, Eleni becomes pregnant, eventually giving birth to healthy little boy whom they name Ianni. They do not know whether Ianni is a carrier of thalassaemia but do not at this stage feel that they need to know. When the baby is several weeks old they take him back to the clinic to show him off to the doctor who had given them genetic advice. He told them of his research: within five years we will be able to use genetic modification techniques on in vitro embryos in order to eliminate the genetic 'fault' completely. There would then be need to worry about carriers passing on the problem to future generations. This is called germ-line gene therapy. The doctor explained that the preliminary results were very encouraging but at present the law prevents any genetically modified embryo from being implanted in the uterus, even those modified for therapeutic reasons.
Should germ-line gene therapy be legalised? Why?