Deaths from cardiac valve diseases appear to run in families, suggesting a significant genetic component, according to a study published in Circulation: Journal of the American Heart Association.
“These findings suggest that unknown genetic factors contribute to death due to mitral valve disease and death due to non-rheumatic aortic valve disease,” said Benjamin Horne, lead author of the study and a Ph.D. candidate in genetic epidemiology at the University of Utah’s department of medical informatics in Salt Lake City. “Future studies will attempt to discover the genes responsible for such risk.”
The mitral valve is located between the heart’s left atrium and left ventricle. The aortic valve is between the left ventricle and the aorta. Non-rheumatic refers to not being caused by rheumatic fever.
Using death certificates and genealogy data from the Utah Population Database, researchers studied people who died of aortic and mitral valve disease. The broad database makes the study unique, researchers said.
“While some small studies have suggested that some types of mitral valve disease may aggregate in families, this study used a population database that included millions of individuals across several centuries with their genealogical relationships to each other and with 250,000 death certificates for those from the 20th century,” said Horne, who also works in the cardiovascular department at LDS Hospital in Salt Lake City.
The familial clustering observed was especially strong among those who died of non-rhuematic mitral valve disease, with first-degree relatives of a person with mitral valve disease being more than two-and-a-half times more likely to die of mitral valve disease. The second-degree relatives of those who died of mitral valve disease also were 67 percent more likely to die of the disease, despite only sharing half as much DNA as do first-degree relatives.
In the study, analysis of non-rhuematic fever related deaths showed that 932 deaths were due to aortic valve disease, 1,165 to mitral valve deaths, and 2,504 deaths to disease in any valve including the aortic and mitral valve (with the 407 additional deaths attributed to the tricuspid, pulmonary or unspecified valve, with “unspecified” composing the majority of these).
Horne said the degree to which the valve diseases appeared to aggregate in families was surprising. “It was a similar or greater degree than for other diseases such as breast cancer and prostate cancer for which major genes have been found. This suggests that it is promising that we will be able to find genes for the valve diseases.”