Saturday, October 17, 2009

Advances in Gene Therapy- Sickle Cell Anemia PKU

With the advances in technology, treatments have become available for some genetic diseases. New knowledge and understanding in the genetic link to specific disorders allows science to decrease the effects of the disease, assist in the treatment, decrease the mortality rate associated with the diseases, and the potential to actually cure or prevent the diseases.

Genetics are not the only character influencing the emergence of specific diseases and disorders. The developmental stage and the environment also play a role in the expression (Gauvin, 2009). Testing can indicate the likelihood of the emergence of certain diseases, such as PKU. One test, AFP assay, or Alpha fetoprotein assay, is a maternal blood tests that reveals if the PKU recessive allele is present (Gauvin, 2009). The detection of these recessive alleles can be conducted before and after birth (Gauvin, 2009).

Women who are found to carry the PKU recessive allele are recommended to take a special diet, typically for life, but at the very least, during pregnancy (Gauvin, 2009). Failure to follow this diet may lead to miscarriage or the the increased risk of the baby having significant mental retardation (Gauvin, 2009). After the baby has been born, the testing can also occur. Babies are tested to determine if the phenylalanine is decreased and preventing the build up of toxins that lead to mental retardation (Gauvin, 2009). If detected, a special PKU diet must immediately be implemented and continued until the nervous system of the infant matures (Gauvin, 2009).

Another disease, sickle cell anemia, is finding hope in the strides of gene therapy and testing measures resulting from the research in genetic disorders and genetically linked diseases. Sickle cell anemia is more prominent in African American populations and 8% of African Americans carry the recessive gene for Sickle Cell Anemia (Gauvin, 2009). Sickle Cell Anemia results when 2 recessive alleles are expressed in combination with each other (Gauvin, 2009). With this disease, the red blood cells decrease in oxygen, resulting in the disfiguration of the cell into an elongated shape which gets caught in blood vessels leading to pain, tissue damage, chronic anemia, and possibility of death (Gauvin, 2009).

Historically, the only treatments available were blood transfusions (Gauvin, 2009). Some pharmaceuticals have been found to help with the symptoms by increasing the activity of dormant hemoglobin genes (Gauvin, 2009). The progress in gene therapy has led to hope for more effective and life saving treatments. Gene therapy involves using normal alleles to compensate for the dysfunctional alleles that lead to the disorder or disease (Gauvin, 2009). In Utero treatments that have been tried utilized bone marrow cells from the father being injected into the fetus through the mother’s abdomen (Gauvin, 2009). Safety is always a concern, even though the use of ultrasound serves as a guide (Gauvin, 2009). Another measure used is the removal of the target cells and then fusing them with the new genes, and then re-inserting them into their target place within the body (Gauvin, 2009).
Obviously medical procedures and science is moving forward quickly. The benefits of these measures include preventing diseases, curing disease, and the possibility of eventually eliminating such diseases. Genetic counseling continues to play a significant role in determining the presence of these defective alleles and determining the risks they present to the infant.

It is important to slow down, though, and consider the negative impacts of such zealous measures. Do these defective alleles have a purpose within the human development realm? Sickle cells, for example, have been found to have a positive purpose for the survival of humans. Sickle cells have been determined to also fight malaria, as their unique formation is genetically resistant to the disease that kills thousands every year (Gauvin, 2009). So, science needs to explore all of the possible outcomes of genetically altering the human cells, even if the intent is to preserve life and prevent suffering.

Valerie Poling


Gauvin, P. (2009). Child Psychology: A Contemporary Viewpoint, 7th ed. In C. U. HASOP, Psychology Human Prenatal Development (pp. 3-36). McGraw-Hill Primis.

To my readers? What do you think? Are these advances, "Playing God"- are we altering human nature? Are we ridding society of unique and individual characteristics? Are we stigmatizing those that do present themself with a special characteristic such as mental retardation? Obviously no one wants their child to suffer or feel pain, but as with sickle cell, is there a higher purpose for these characteristics that we may not know?

I would love to hear your take on these advances, gene therapy, etc. I have not personally had to undergo or utilize such testing, so it has not touched me personally, but for some of you- maybe it has... Please share your thoughts and enlighten someone else to a different point of view...

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