Pre-implantation genetic diagnosis (PGD) & haplotyping (PGH)

Alternative uses for PGD;
PGH; Recent developments

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One alternative use for PGD:

Some people are seriously ill or dying, but can be treated or cured with a transplant from a suitable donor. For example, people who suffer from leukemia, aplastic anemia and other potentially life-threatening blood diseases can often be cured with a bone marrow transplant (BMT) from a compatible donor. Too often, sick people die because a matching donor cannot be found.

PGD offers an alternative way of finding a compatible donor -- by creating one. The patient's mother can go through a standard IVF procedure, have many ova harvested, have the ova fertilized by the father's sperm, and have the resulted embryos go through a PGD procedure. If any embryos are found to contain DNA that is an appropriate match to the patient, they can be implanted in the mother's uterus. With luck, a pregnancy will develop and an infant will be born. That infant may then be able to supply needed stem cells from his/her umbilical cord or some other body component to their sibling and save their life. 

To some parents, this option is literally a life saver. Instead of watching their child waste away and die, they can have the possibility of a cure. Also, another child will be added to their family. The first family to go through this process was the Nash family in Colorado. Their child:

"Molly was born with Fanconi anemia, a rare genetic disease that causes many problems, the most serious of which is inadequate bone marrow production....her poor bone marrow production meant that she would develop leukemia and die, possibly within a few years." 

The Nashes wanted a second child anyway. IVF and PGD procedures assured that their second child would be disease free and would be a compatible donor to their sister. A month after Adam was born Molly was treated with radiation and chemotherapy to completely destroy her bone marrow. She was then given a transfusion of Adam's umbilical cord blood. Her chances of survival increased from 42% with cord blood transplant from an unrelated marrow donor to 85% with a transplant from a matched sibling. There was no danger at all to Adam. ₁

There are some negative aspects to the use of IVF and PGD to create a child to treat her or his sibling:

Another alternative use for PGD:

Advanced Cell Technology (ACT) in Worcester, MA conduct world-class research with stem cells. They suggest that when fertility clinics perform human PGD to detect genetic diseases, they could:

Lines of stem cells would then be created as a byproduct of existing PGD testing. No embryo would be killed in the process. The scientists hope, perhaps naively, that this technique might be acceptable to the pro-life community.

More information.

Pre-implantation Genetic Haplotyping (PGH):

In 2004,Ali al-Hellani, a Saudi Arabian fertility specialist, pioneered a more advanced technique called PGH. Pamela Renwick at Guy's hospital genetics centre and Prof Braude, who runs a fertility center at Kings College, London further refined the method. ₃ Braude said:

"It is more accurate, highly reliable and available for a whole range of disorders. It opens the doors to all sorts of conditions." ₄

PGH overcomes the main deficiency of PGD: it can only be used when the physicians is looking for one of the 200 or so diseases that have already been typed.

The PGH procedure involves taking blood samples from the couple, and from their child or another relative who is affected by a disease, They fertilize several ova, allow them to develop normally for three days, and then remove a single cell from each. This cell is grown overnight in the laboratory, using multiple displacement amplification to produce a large DNA sample. The doctors can compare the DNA from relatives who are affected by the disease with the DNA from other relatives that are disease free. They can identify the region of a chromosome that causes the disease. They can then determine whether a given embryo is unaffected by the disease, or is a carrier of the disease, or is destined to develop the disease. ₃

The Daily Mail reported:

"From this the scientists can spot if the embryo is carrying the problem chromosome or a disease-free version. Only the healthy ones are then implanted." ₄

The Guardian reported that almost 6,000 diseases and disorders can be sensed with this technique, including Duchenne's muscular dystrophy (DMD), fragile-x syndrome and some forms of cystic fibrosis. Stuart Lavery, a fertility expert at Hammersmith hospital, London, said that

"The idea of a universal tool that can be applied regardless of what the mutation is means many more patients will have access to this." ₃

Some recent developments:

"The human fertilisation and embryology authority, which regulates all such work in the UK, and the advisory committee on genetic testing (ACGT) yesterday published a consultation paper in print and on the internet. They claim this is the first such public consultation in the world. "

"They want to know whether the public finds it acceptable for genetic technology to be used to screen embryos to eliminate those that would be born with distressing inherited diseases, such as cystic fibrosis. If such screening is acceptable, the two bodies are asking, then how far should it go? What sort of severity of disease should the labs be allowed to screen for? If it becomes possible to detect a genetic mutation that will lead to a non-life threatening disability such as deafness, what should be done? " _5,6

"The Law Lords backed a 2003 Court of Appeal ruling that some couples undergoing the fertility treatment could have their embryos screened to find tissue matches for seriously ill children, Advocates say the procedure will help save desperately ill children. Opponents fear it could lead to the creation of babies for spare parts." ₇

References used:

The following information sources were used to prepare and update the above essay. The hyperlinks are not necessarily still active today.

1. "The Nash family: miracle baby," University of Minnesota Cancer Center, at: http://www.cancer.umn.edu/
2. Malcolm Ritter, "Studies show new ways to get stem cells," Associated Press, 2005-OCT-16, at: http://news.yahoo.com/
3. Ian Sample, "New embryo test to screen for 6,000 diseases," The Guardian, 2006-JUN-19, at: http://www.guardian.co.uk/
4. Julie Wheldon, "Ethical row erupts over designer babies breakthrough," Daily Mail, 2006-JUN-19, at: http://www.dailymail.co.uk/
5. Sarah Boseley, "Public views on embryo genetic testing sought," http://www.guardian.co.uk/
6. "Consultation document on preimplantation genetic diagnosis," The Human Fertilisation and Embryology Authority, at: http://www.hfea.gov.uk/
7. "Court lets couples create babies to cure ill siblings," The Toronto Star, 2005-APR-29, Page A16.

Copyright © 1999 to 2007 by Ontario Consultants on Religious Tolerance
Latest update: 2007-SEP-20
Author: B.A. Robinson