Lebers Congenital Amaurosis, LCA, is a rare genetic disorder that affects the retina. It affects roughly 3000 people in the United States. It is caused by a genetic mutation in 1 of a possible 14 genes. For those of you who do not understand genetics, there are dominant and recessive genes. And all genes come in pairs... it can be two dominant, one dominant and one recessive, or two recessive. Each parent passes on one gene.
In order to have LCA, each parent would have to pass on the recessive form of the exact same gene... and since 14 genes can cause LCA, the odds are pretty low. Specifically, its only a 1 in 80,000 chance.
The specific mutation Nomaan has is in the RPE65 gene.
RPE65 is responsible for breaking down vitamin A into a form that the retinal cells need to function. Without it, the retinal cells slowly start to die. With time, the retinal cells begin to scar over.
LCA is diagnosed using signs and symptoms and an ERG. it is confirmed by genetic testing.
It is a degenerative disease, and with time, leads to total blindness. The retinal deterioration rate varies from person to person.
In Nomi's case, the LCA causes him to be extremely sensitive to light, both too low and too bright. In either situation he can barely see anything. The lighting has to be just perfect for him to be able to see anything at all. He has nystagmus (rapid shaking of the eyes). He has very poor peripheral vision. He has a hard time distinguishing certain colors. He has limited depth perception. And he is extremely far sighted.
At the time of Nomi's ERG in April of 2011, Dr. Borchert found that he had already lost 90% of his retinal function.
In order to have LCA, each parent would have to pass on the recessive form of the exact same gene... and since 14 genes can cause LCA, the odds are pretty low. Specifically, its only a 1 in 80,000 chance.
The specific mutation Nomaan has is in the RPE65 gene.
RPE65 is responsible for breaking down vitamin A into a form that the retinal cells need to function. Without it, the retinal cells slowly start to die. With time, the retinal cells begin to scar over.
LCA is diagnosed using signs and symptoms and an ERG. it is confirmed by genetic testing.
It is a degenerative disease, and with time, leads to total blindness. The retinal deterioration rate varies from person to person.
In Nomi's case, the LCA causes him to be extremely sensitive to light, both too low and too bright. In either situation he can barely see anything. The lighting has to be just perfect for him to be able to see anything at all. He has nystagmus (rapid shaking of the eyes). He has very poor peripheral vision. He has a hard time distinguishing certain colors. He has limited depth perception. And he is extremely far sighted.
At the time of Nomi's ERG in April of 2011, Dr. Borchert found that he had already lost 90% of his retinal function.
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