Gene Therapy- Hemophilia
Genetic Therapy that focuses on hemophilia
Gene therapy is reinserting certain genes that helps deal with genetic diseases. There are three basic forms of this gene therapy. The first is Gene Inactivation Therapy in which the transferred gene neutralizes the proteins and evens out the amount or rids of the defective proteins. Another type is Gene Augmentation Therapy where the original form of the gene or the normal form of the gene is inserted into one of the cell’s chromosomes. This procedure is used normally when a gene with little activity or a deleted gene is the cause for the genetic disease. The third type of gene therapy is Gene Replacement Therapy. This form is used when the genetic disease involved specific genes that are necessary for proper functioning. The normal gene being put in place of the mutant gene accomplishes this form of gene therapy.
Either transduction or transfection can be used to get the therapeutic genes into the patients system. Transfection is when the genes are introduced physically or chemically in a way that allows the cell membrane to be temporarily permeable to a foreign DNA. In the second method used for gene therapy, transduction, there is a beneficial gene added into the genetic material of the virus, which then is allowed to infect the target cell which is the indirect transfer method for gene therapy.
There have been four somewhat recent successful gene therapy treatments. The four deal with correcting hemophilia, bone marrow transplants, skin cancer, and vessel growth. In the success with the bone marrow transplants, French researchers collected bone marrow cells from patients, used gene therapy to correct the bone marrow, and then returned the bone marrow to the patient. This was 80% successful as reports 16 months after the transplants showed. Squamous cell carcinoma, skin cancer of the head and neck, was treated using gene therapy as well. The fourth trial was where DNA was used to carry a substance that stimulates blood vessel growth to damaged heart tissue and in this trial there was much success noted.
The beginning of Gene Therapy began in the late 1980’s, which was completely unsuccessful. In the fall of 1999 the death of University of Pennsylvania trial participant, Jesse Gelsinger was followed by much public outcry and legal problems that put an immediate halt on all gene therapy research. The reason Jesse was being treated with Gene therapy was to attempt to cure the teenager’s rare liver disease. In the long run, the outcome of a government investigation concluded that researchers had not followed the rules. The FDA had all research put to a stand still until an appropriate monitoring and reporting system had been approved and was in place.
As you can guess, each of these gene therapy procedures was first tested on animals. First, the virus, hemophilia B was injected into the dogs in the form of a virus. Then the dogs were treated with gene therapy and given the appropriate missing genes and adding them to muscle cells, which would accept the genes, and then produce the proper clotting factor and the clotting of the dog’s blood would be about back on track. The result show that the blood-clotting times decreased from more than on hour down to about 15-20 minutes where as a normal dog’s blood-clotting time is approximately six minutes. No side effects or problems were reported as a result of the treatment. Researchers at Stanford University School of Medicine had a similar outcome when they experimented, first on mice, then on dogs as well.
(The process here shows how the new gene or foreign DNA is added into the nucleus of the chromosome with the help of the virus, represented here as AAV Vector)
Gene therapy that treats hemophilia has been an increasingly popular method to take cure hemophilia A and B. Hemophilia A is the more common form that is caused by a missing gene used as a blood-clotting factor. A single gene introduced into an affected person can treat the disease. Hemophilia B is much easier to treat, and often preferred by some therapy labs. The reason that it is easier to treat is because the defected gene found in hemophilia B, is smaller
