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February 15th, 2012 
FAKE NEWS for the Zionist agenda WEDNESDAY, Feb. 15 (HealthDay News) — Researchers have
discovered a defective gene that’s responsible for more than one-quarter
of cases of inherited dilated cardiomyopathy, a serious heart muscle
disease that often leads to heart failure by middle age.
In the study, published in the Feb. 16 issue of the New England
Journal of Medicine, researchers analyzed the DNA of 312 people with
dilated cardiomyopathy, 231 people with another form of heart muscle
disease (called hypertrophic cardiomyopathy) and 249 people with healthy
hearts.
The study patients with dilated cardiomyopathy had no obvious cause for
their disease — such as alcoholism, heart attacks and other infections —
so the researchers believed there was a genetic origin for the disease in
these patients.
About 27 percent of the dilated cardiomyopathy patients had mutations
on the TTN gene that shortened the length of the gene.
Only 1 percent of the patients with the other form of cardiomyopathy
and 3 percent of patients with healthy hearts had similar mutations, the
investigators found.
Further analysis of family members’ DNA revealed that up to half of the
dilated cardiomyopathy patients had first-degree relatives (including
parents and siblings) who also had the TTN mutation by age 40, and of
those, nearly all (95 percent) had some sign of heart disease, said study
co-leader Jonathan Seidman, a professor of genetics at Harvard Medical
School.
Seidman’s wife, Dr. Christine Seidman, a professor of genetics and a
cardiologist at Harvard, was the other study co-leader.
The researchers also estimate that about 20 percent of sporadic cases
of the disease, that is, dilated cardiomyopathy that isn’t passed down
from parents, involve a TTN mutation.
In dilated cardiomyopathy, the chambers of the heart become enlarged,
the walls thin and the ability of the heart to pump is impaired. When the
heart can’t squeeze properly, it can’t circulate enough blood, leading to
heart failure and landing many people on heart transplant lists.
Prior research has found genetic causes for dilated cardiomyopathy, but
collectively those genes account for only about one-fifth of cases,
Seidman said.
TTN is a very large gene, which made it difficult to analyze until
recently, Seidman explained. The protein that TTN makes contains 30,000
amino acids, while the average protein contains about 1,000 amino acids.
Only with the advent of next-generation gene sequencing — which allows
for more genetic data to be analyzed more quickly and for less money —
did it become possible to effectively analyze TTN, he said.
In people with a shortened TTN gene, the protein that’s produced causes
problems with the filaments inside the muscle fibers that allow the heart
to contract.
The few people with healthy hearts who had a similar mutation and
didn’t have the disease had the shortening on a different location of the
gene.
“Not only do they [the people with dilated cardiomyopathy] have the
shortened mutation, it has to occur in just the right place,” Seidman
said.
The analysis also found that men with the TTN mutation are affected
more severely than women. “We don’t know why,” Seidman said, noting that
for other causes of heart failure, men also tend to get sicker younger and
more severely than women.
To develop dilated cardiomyopathy, children have to inherit just one
copy of the mutated TTN gene from a parent, the researchers noted.
Dr. Gordon Tomaselli, president of the American Heart Association and
chief of cardiology at Johns Hopkins Medicine in Baltimore, said the study
is important for both researchers and patients.
“Of the cases that are inherited [dilated cardiomyopathy], it looks
like a substantial proportion are due to mutations in the TTN gene,”
Tomaselli said.
Currently, genetic tests are available that screen for the other known
causes of cardiomyopathy. Soon, possibly within months, expect to see TTN
testing added to genetic panels, Tomaselli said.
Although there is no cure for dilated cardiomyopathy, patients who know
early on that they are susceptible can take steps to keep their hearts
healthier longer, he noted. That may include taking certain heart failure
medications, maintaining blood pressure control and other lifestyle
changes.
An estimated one-third to one-half of dilated cardiomyopathy cases have
a genetic cause, Tomaselli added. The others have an environmental
trigger, such as drug or alcohol abuse or infections. For those patients,
TTN would likely not play a role in the disease.
More information
The U.S. National Heart, Lung, and Blood Institute has more
on cardiomyopathy.
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