Achromatopsia-Discussion

Discussion

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 * Achromatopsia is a pleiotropic condition which make it difficult to determine one gene that is involved in the cause. Despite this, researchers have discovered that the genes CNGB3, CNGA3, GNAT2, and PDE6C are the most commonly associated genes.
 * There are currently no treatments available for patients suffering from achromatopsia. Gene therapy is being explored to determine if it can produce successful results for restoring colored vision. Clinical trials on non-human species have been performed, both with successful and partially successful results.


 * Gene therapy for achromatopsia was first introduced in dogs. Successful rod regeneration in canines have shown the possibilities of this process. Canines with complete achromatopsia displayed fully restored color vision following the subretinal injection procedure. The success of this therapy can provide information on how to administer the corrective gene (through viral vectors) as well as the efficacy of the therapy.


 * Another study was preformed using monkeys with incomplete achromatopsia. The procedure also used viral vectors with the goal of increasing light sensitive proteins (L-opsin) in the retina. Although light sensitivity was increased, colored vision was not restored completely.


 * It is predicted that the difference in canine and primate genomes are the reason for the different outcomes. Similar procedures were performed, but the therapies provided canines with normal vision while the monkeys were left achromatic. What is different about the two species, is their genomes. It is possible that different genes are the cause of achromatopsia for each genome, therefore the results would be different because the therapy is performed on different genes.


 * Human genomes are most closely related to primate genomes. This suggests that the result of gene therapy on humans would most closely resemble that of the monkey studies. Further research is necessary before gene therapy can be performed on humans because the current research doesn't provide evidence that the therapies will work for humans. Additionally, the fact that this research was performed on incomplete achromatopsia promotes the hypothesis that complete achromatopsia is more responsive to therapy.


 * It is predicted that different genotypes may effect the efficacy of the treatment. An individual with one allele may react positively to gene therapies, while someone with a different allele on the same gene may not be affected by the therapy. It is necessary to determine the specific gene(s) that are involved in the lack of visual acuity as well as the individual genotype(s) that would be "fixed" in the process.


 * Understanding the individual's specific genetic makeup can help determine the necessary route of treatment (which protein and gene should be targeted and using which type of viral vector).

Introduction Materials and Methods Results Broader Impacts Work Cited