March 2, 2012

Healthy Family, Healthy Life?

(Ivanhoe Newswire) -- What if reconstructing your family tree could possibly help save your life?

A study by Dutch researchers have estimated the death risk for people who have inherited heart rhythm disorders by looking at family trees dating back to 1811.

The family trees revealed the risk for sudden cardiac death increases for people who carry rare genes and have symptoms of fainting. Before this study was conducted, the risk in people who carry this gene was uncertain because they didn't have symptoms. Physicians had to develop preventive measures without an idea of the death risk that involved implanted devises and medications that can cause side effects.

Researchers used Dutch archives to reconstruct family trees for people with different conditions and compared death statistics in 266 patients who carried the mutated gene linked with arrhythmia, the general population, and 904 family members with a 50% chance of also having the mutation. They were able to identify age ranges during which the risk of death increased for people who possessed the mutated gene and their family members who had not yet been treated or diagnosed. The mutations that were studied are rare, but if one carries it, their children are 50% more likely to inherit it as well.

"The information can help doctors know when to treat and screen families with arrhythmia syndromes caused by different gene mutations. We have to be careful not to draw conclusions with arrhythmias caused by different mutations. However, this new data can guide screening. In LQTS1, we advise starting genetic and heart screening of first-degree family members (children, siblings, parents) at a very young age," Eline A. Nannenberg, M.D., lead researcher of the study and a clinical geneticist at the Academic Medical Centre in Amsterdam, The Netherlands, was quoted as saying.

Researchers found in long QT syndrome, (a condition related to sudden infant death syndrome) death risk was high throughout childhood, but particularly in the first 10 years for one mutation (LQTS1). In Brugada syndrome excess deaths occurred between ages 40-59 and were primarily males. For SCN5a-overlap syndrome (where SCN5a gene mutation affects the way heart cells respond) deaths start to increase at age 5 and peak at 20 to 39, and for catecholaminergic polymorphic ventricular tachycardia (CPVT)(a condition that causes fainting) death risk was highest at 20-39.

SOURCE: Circulation: Cardiovascular Genetics, March 2012