Danon Disease Can Be Quickly Fatal, S...( Heart experts stress the importance o...),Health

Heart experts stress the importance of genetic testing and diagnosis

TUESDAY, March 24 (HealthDay News) -- A rare genetic heart disorder called Danon disease progresses rapidly and is often deadly in young people, according to a new study.

The recently recognized disease is a type of cardiomyopathy, or heart muscle disorder, linked to genetic mutations in the lysosome-associated membrane protein gene (LAMP2). Until now, the natural course of the disease was unclear.

Researchers from the Minneapolis Heart Institute Foundation studied seven people diagnosed with Danon disease when they were 7 to 17 years old. In six of them, diagnosis was made as the result of a heart murmur, family screening and findings on routine electrocardiogram tests or from such symptoms as chest pain and fainting. In one person, atrial fibrillation, an abnormal heart rhythm, led to the diagnosis.

Within nine years of diagnosis, on average, all seven had encountered serious problems. One person had a heart transplant, and four died of acute or progressive heart failure. Their deterioration was often rapid, going from having few or no symptoms to end-stage heart failure within as little as six months.

The other two people in the study had sudden, unexpected, major arrhythmic events, and one of them died suddenly from ventricular fibrillation -- very rapid, uncoordinated contractions of the ventricles -- that was not controlled by an implantable cardioverter defibrillator.

All seven developed problems with contraction of their left heart ventricle, called left ventricular systolic dysfunction. All seven had a defibrillator implanted, but in five of them, the devices failed to prevent lethal tachyarrhythmias -- excessively rapid heartbeat accompanied by irregular heartbeat.

The final electrocardiograms examined by the researchers showed significant enlargement of the left ventricle in all seven, the study reported.'/>"/>