Hamburg, Germany - A team of German scientists say they have found a genetic cause for mysterious sudden deaths of perfectly healthy athletes who collapse and die of cardiac arrest.

German researchers at Heidelberg University Hospital claim to have discovered a seemingly insignificant genetic modification that may in fact spawn a potentially, fatal cardiac condition.

In tests on zebra fish, the researchers located a single "false" amino acid which resulted in a hazardous heart condition. Since the fish have a genetic make-up similar to that of humans, these defects could be critical for humans as well, according to a statement reported by EurekAlert.

Cardiac insufficiency is not just a disease that results from a heart attack or myocarditis. For young people in particular there is often an underlying genetic cause (cardiomyopathy).

The researchers pointed out that some 30,000 people in Germany are affected and the disease often remains undetected for a long time.

The tragic cases of seemingly healthy athletes who suddenly collapse during training or competition are well known.

The renowned Heidelberg University Hospital cardiac research team led by Hugo Katushas been studying zebra fish for years because of the similarities in genetics between the fish and human beings.

A research sub-group led by Benjamin Meder and Christina Laufer from Wolfgang Rottbauer's cardiological research group examined a heart muscle protein called myosin light chain-1, which is involved in contraction of the heart muscle. They discovered the crucial change in the amino acid Serine 195, which was lost through mutation.

This single change is sufficient to limit heart function severely.

But the researchers cautioned that much more research is needed. In the next step, the Heidelberg cardiologists plan to search for the same mutation in patients' genes.

Since approximately 70 per cent of human genes are identical with those of zebra fish, the researchers are confident that a Serine 195 mutation will have a similar affect in human hearts. The researchers also hope to develop new therapies for patients.