Researchers find gene linked to heartbeat irregularities

Thursday, January 9th 2003, 12:00 am

By: News On 6

SEATTLE (AP) _ A gene mutation linked to atrial fibrillation, a type of heartbeat irregularity, has been identified by researchers who studied four generations of Chinese family with a history of the disorder.

In a study appearing this week in the journal Science, Chinese and French researchers report that a mutation on a gene called KCNQ1 is the apparent cause of an inherited form of atrial fibrillation.

Atrial fibrillation affects more than 5 percent of everyone over the age of 65. The disorder lowers the pumping efficiency of the heart. It can cause blood clots, other types of heartbeat irregularities and heart failure.

To find the gene, researchers performed genetic screening on 44 members of a Chinese family with a history of atrial fibrillation. Sixteen of the family members were diagnosed with the disorder, some developing it at a young age. The family members lived in both rural villages and cities in Shandong Province.

Researchers found a mutation in the KCNQ1 gene among the affected family members, but not in those without the arrhythmia. They also screened 188 healthy, unrelated people and did not find the mutation.

Analysis of the gene mutation in laboratory cells showed that the gene disrupted the flow of potassium through cell membranes in the heart. Potassium plays a key role in the heartbeat.

Finding genes that cause a disorder can lead to a better understanding of its cause which, in turn, helps scientists to develop new therapies.

The 20 co-authors of the study Science are from five research centers in the People's Republic of China and a drug research center in France.