Dogs and vision-impaired humans have long had a close relationship but this relationship may grow closer as genetic research continues into an inherited condition, Leber congenital amaurosis (LCA), which causes blindness. LCA affects dogs and human infants and involves a defect in genes responsible for the retinas ability to translate light into nerve impulses. In humans it is an autosomal recessive disease thought to be caused by mutations leading to abnormal development of photoreceptors.
Genetic researchers have been able to restore the sight of a group of dogs born with LCA by injecting cells into their eyeballs that contained a modified, functional form of the genes that cause LCA. Previous studies had improved sight using rodents as models.
So the question must be asked: Can the same genetic manipulation be used to treat this condition in humans? It is not as simple as it sounds. The genes that cause LCA in humans vary. The portion of the gene mutated in one LCA sufferer may not be the same portion in the next. Accurately identifying the genes involved would first be necessary; this is underway through genetic research.
Human treatment would require therapy prior to birth which raises ethical issues.
However, human treatment is certainly within the realms of possibility. The benefit to dogs may already be available, the benefit for humans may not be out of reach – our relationship with man’s best friend continues to grow.
Written by: Hannah Kingshott
Primary resource:
http://www.nature.com/ng/journal/v28/n1/pdf/ng0501_92.pdf
Secondary Resources:
http://www.abc.net.au/science/news/stories/s283715.htm
http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&partid=1298
For further information relating to LCA:
http://rarediseases.about.com/od/rarediseasesl/a/lca05.htm
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