Genetic tests for an inherited heart disorder are more likely to have incorrect results in black Americans than in whites, according to a new study that is likely to have implications for other minorities and other diseases, including cancer.

Mistakes have been made because earlier research linking genetic traits to illness did not include enough members of minority groups to identify differences between them and the majority white population or to draw conclusions about their risks of disease.

The new study, published Wednesday in The New England Journal of Medicine, focused on hypertrophic cardiomyopathy — a thickening of the wall of the heart that can cause abnormal rhythms and sudden death. The condition often has no symptoms, but can cause young athletes to pass out or even die during the intense activity of their sport. It can be caused by inherited mutations in one of 10 to 20 genes, and affects one in 500 people in the United States. More than 1,000 mutations have been linked to the condition.

Genetic testing can identify people who have suspect mutations, and is frequently offered to family members of those who have the disease. But now researchers have found that after genetic testing, black people are more likely than whites to be told mistakenly that they are at risk.