The heart disease: the genes responsible still elusive

The researcher try one approach in understanding disease by find what are genes are responsible in the particular disease (the common genes express in patients). The type of study begin 5 year ago when a study of 146 Caucasian volunteers turned up a common gene variant among those with the eye disease macular degeneration.

Researchers had used a new strategy: They scanned large stretches of the genomes of the sick and the healthy and found a single DNA base that was much more likely to be present in those whose eyes were failing.

The finding was remarkable: Relatively few people participated in the study, yet those with two copies of the suspect gene variant had 10 times the risk of macular degeneration, a huge increase. Furthermore, the method the group used, called genome-wide association (GWA), had some big advantages: It was unbiased, testing thousands of gene-disease associations at once, not just a researcher’s favorites. And it pointed to common variants, found in at least 5% of individuals studied. GWA studies offered hope of identifying people at risk for diseases, uncovering new disease mechanisms, and finding new targets for therapy.

The researcher also used the GWA studies in the heart disease. But the results are not like expexced. “People did studies with 300 or 500 people and didn’t find anything, then did 1000 and didn’t find anything,” says Deepak Srivastava, who directs the Gladstone Institute of Cardiovascular Disease at the University of California (UC), San Francisco. It quickly became clear that macular degeneration was an exception.

The results from one group of GWA studies, for heart disease, are typical, with a mixed record and an uncertain legacy. The technique has identified dozens of variants, but all have weak effects; so far, almost none has led to DNA changes that actually cause disease. Researchers have had more success finding variants that link to tightly defined conditions like high cholesterol than to heart failure, a catch-all disease.

For me I suggest that the GWA studies must be more specific to what causes of heart disease so may be we can know what genes cause particular heart disease.