AsianScientist (Aug. 1, 2012) – An international team, led by researchers in China, has identified novel gene mutations linked to Leber congenital amaurosis (LCA), one of the most common causes of inherited blindness in children.
An estimated 3 out of every 100,000 newborns have LCA, an inherited retinal degenerative disease characterized by severe loss of vision at birth.
Previous studies have found that LCA may be caused by mutations in a number of genes which are necessary for normal vision and play important roles in the development and function of the retina.
Restoring gene function by gene replacement therapy has been successful in animals and human studies are currently underway. However, known LCA-associated gene mutations cannot account for all LCA cases, with the genetic cause still unknown in 20-30 percent of LCA patients, presenting an obstacle to effective gene replacement therapy.
In the latest study, published online in Nature Genetics, the researchers sequenced the whole exome of an LCA patient with no previously identified mutations.
From a list of over two thousand possible mutations, they pinpointed the NMNAT1 gene as the most likely candidate that caused LCA in the patient. Previous studies have shown that NMNAT1 plays an important role in degeneration of nerve fibers.
The researchers analyzed the NMNAT1 gene in 50 unrelated LCA patients with no previously identified mutations and found ten patients carrying NMNAT1 mutations.
They also observed a correlation between the types of NMNAT1 mutation and the severity of LCA: patients carrying two mutations (one missense mutation and one nonsense mutation) were all blind at birth; while those who carried only the missense mutation developed poor vision a few years after birth.
The article can be found at: Chiang (2012) Exome Sequencing Identifies NMNAT1 Mutations As A Cause Of Leber Congenital Amaurosis.
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Source: BGI.
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