Posted on 08/10/2007 7:35:13 PM PDT by neverdem
Researchers have discovered the genetic flaws that underlie a major type of glaucoma, a leading cause of blindness. By pinpointing what goes wrong, their finding may provide a basis for devising new treatments.
The finding is part of a continuing wave of discoveries about the genes underlying common diseases. The wave began this spring as researchers reported the first results using a new device, DNA-scanning chips containing information on up to 500,000 genetically variable sites across the human genome.
By comparing the genomes of patients with those of people in good health, researchers can identify which of the variable sites are associated with the disease and so locate the causative genes.
Many efforts to locate disease genes have proved unreliable, but most geneticists are confident that the new method, known as whole genome association, is working. In the last few months, studies using whole genome association have identified genes or genetic elements involved in at least 10 major diseases.
The finding on glaucoma, reported yesterday in the journal Science, is from researchers at the Icelandic gene-hunting company deCODE Genetics, the National University Hospital in Reykjavik, Iceland, and Uppsala University in Sweden. By studying 16,000 patients in Iceland and Sweden, the researchers have identified two variant sites on the genome that confer risk for a common type of the disease, known as exfoliative glaucoma.
Both sites lie in the same gene, known as the lysyl oxidase-like 1 gene, or LOXL1, and together account for more than 99 percent of the disease. This means that defects in a single gene account for essentially all cases of exfoliative glaucoma, said Dr. Kari Stefansson, chief executive of deCODE Genetics. The finding is surprising, Dr. Stefansson said, given that most common diseases analyzed so far are caused by several genes.
Exfoliative glaucoma can occur when...
(Excerpt) Read more at nytimes.com ...
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