MGH studies heart attacks
Coronary heart disease, America's number one killer, is responsible for
one out of every five deaths in the country each year. In 2006 alone,
more than 865,000 people suffered a heart attack — also known as
myocardial infarction, or MI. The most common risk factors associated
with coronary heart disease are high cholesterol, hypertension, smoking
According to two MGH researchers, however, a person's genes also may play
a role in determining his or her risk for MI. David Altshuler, MD, PhD,
of the Department of Molecular Biology, and Sekar Kathiresan, MD, of the
MGH Cardiology Division, recently were awarded a $4.3 million grant by
the National Heart, Lung, and Blood Institute (NHLBI) for the study, "A
Genome-wide Association Study for Early-Onset Myocardial Infarction."
In this study, Kathiresan and Altshuler aim to associate cases of early-onset
MI — heart attacks in younger patients — with genes that may
put the patients at risk. While the average age of a first heart attack
is 65.8 for men and 70.4 for women, this study will target 3,000 male
and female MI patients aged 50 or 60 years or younger, respectively.
There is evidence to support the idea that inherited genetic variations
play a key role in heart attacks, especially in early-onset cases. For
example, MI tends to cluster in families even after traditional risk factors
are taken into account. Due to recent advances in genetics, now it is
possible to search the entire human genome for common variants in DNA
that may influence MI risk. Through chip-based genotyping technology,
this study will test around one million DNA sequence variants for possible
roles in early-onset MI.
Successfully identifying these variants could transform how clinicians
understand and treat heart attacks. If the genomic variants are located
precisely, scientists could develop new diagnostic tests to allow doctors
to identify those most at risk and target their treatments accordingly.
Further, knowledge about these genes could allow clinicians to shed light
on why heart attacks occur. "This may translate into new biology,
new information and new avenues for treatment," says Kathiresan.
"We are hopeful that knowledge about these genes will improve our
ability to predict, prevent and treat heart attacks."
The project was initiated at the MGH in 1998 by Christopher J. O'Donnell,
MD, MPH, an MGH cardiologist and associate director of the Framingham
Heart Study. It later was expanded upon by Altshuler and Kathiresan. In
2006, a $300,000 charitable gift from the Fannie E. Rippel Foundation
provided the seed funding necessary to secure the NHLBI award. Early results
from the project should be available within the next year.