(LifeWire) - When children or young adults die while taking part in sports or other activities, cardiac hypertrophy is often to blame. This rare condition - also called hypertrophic cardiomyopathy - involves a thickening of the heart muscle, making the heart chamber smaller. Recent research has demonstrated the role that genetics plays, raising hopes of improved diagnosis before a child faces a life-threatening cardiac emergency.
Currently, many cases of childhood (pediatric) cardiac hypertrophy -- perhaps 3% to 4% -- are identified only after the death of the child. And nearly 40% of children with definite symptoms of heart muscle defects die or must undergo a heart transplant.
In adults, cardiac hypertrophy is typically associated with high blood pressure or stenosis (narrowing) of the area just beneath the aortic valve. Genetic mutations are also known to be involved. Because the pediatric condition is so deadly, doctors previously thought it was distinct from cardiac hypertrophy in adults. That view is changing.
The 2008 study, in the New England Journal of Medicine, involved 84 children with cardiac hypertrophy. The Harvard Medical School researchers reported that two-thirds of those who had family histories of the condition had distinctive gene mutations. The researchers also found that half of the children who had no family history of the disease also had the characteristic mutations.
When parents of these children were tested, in many cases they, too, had the problem mutations -- even those who experienced no symptoms. While such parents thought they were healthy, echocardiograms in some cases revealed signs of thickened heart muscles. It's not clear why children with cardiac hypertrophy would have serious symptoms while their parents would not.
Discovering the genetic foundations of this disease is significant, but it probably won't transform treatment in the short run because cardiac hypertrophy involves more than genes. Rather, University of Texas researcher Ali Marian writes, it's marked by "complex interactions between genetic and nongenetic factors."In the short term, the main practical benefit may lie in the development of genetic tests to identify siblings or other family members who are at risk. In the more distant future, these discoveries may lead to targeted genetic therapies and more effective treatment.
Read more about hypertrophic cardiomyopathy here.
Sources:
"Cardiac Hypertrophy." cts.usc.edu. 2008. University of Southern California. 22 Oct. 2008 <http://www.cts.usc.edu/zglossary-cardiachypertrophy.html>.
Marian, Ali. "Genetic Determinants of Cardiac Hypertrophy." Current Opinion in Cardiology 23:3(2008):199-205. 22 Oct. 2008 <http://www.co-cardiology.com/pt/re/cocardio/searchplusresults.htm;jsessionid=L2TLTzdZs0GQfP75R4r8ys6VLddjtBlCphL9RzdmkTGl3YL0SpWV!-815685239!181195629!8091!-1?&index=1&results=1&searchid=1#cite1>.
Morita, Hiroyuki, et al. "Shared Genetic Causes of Cardiac Hypertrophy in Children and Adults." New England Journal of Medicine. 358:18(2008):1899-1908. 22 Oct. 2008 <http://content.nejm.org/cgi/content/short/358/18/1899>.
"Shared Causes of Cardiac Hypertrophy in Children and Adults." americanheart.org. 9 Apr. 2008. American Heart Association. 22 Oct. 2008 <http://www.americanheart.org/presenter.jhtml?identifier=3057033>.
