Black Americans Have a Higher Risk of Genetic Misdiagnosis

Laboratories performing genetic tests on an inherited heart disorder may be incorrectly diagnosing black Americans, according to a recent study. The analysis, published by The New England Journal of Medicine, focused on hypertrophic cardiomyopathy, a genetic heart condition that causes sudden death in young athletes. Researchers from Harvard Medical School studied clinical records at leading genetics labs to see if recent patients’ diagnoses included gene mutations now considered benign. They found seven patients who received incorrect diagnoses based on old data, and misclassified gene mutations for black Americans. In fact, the study concludes that black people have a higher chance of being misdiagnosed than whites. This discovery is problematic for black Americans, especially if a child is misdiagnosed. Hypertrophic cardiomyopathy requires expensive medical follow-ups and treatments. Some cases require a surgically implanted device in the chest to prevent abnormal heart rhythms and sudden death. So why are black Americans at risk of false reports? Researchers say it has to do with the first genetic studies done. In previous mutation studies, the numbers of patients tested with African ancestry were significantly lower than those with a European background. To know if a specific gene mutation is the cause of a disease, scientists needed to figure out if the same mutation appears in healthy people too, or if it only appears in those diagnosed. Since there was less sequencing data on healthy patients of African descent, scientists mistakenly labeled some gene mutations as dangerous. Later research disproved those theories. The study also found that some laboratories performing tests for hypertrophic cardiomyopathy have not kept up with recent discoveries, and are still mistakenly diagnosing patients with dangerous mutations. “Even the labs that do keep up may not contact past patients to let them know that their test results are no longer valid,” said Dr. Isaac S. Kohane, the lead author on the Harvard Medical School study, “Researchers do not know how common the problem is.” Hypertrophic cardiomyopathy is when the wall of your heart thickens and causes abnormal heart rhythms. The potentially fatal condition is caused through inherited mutations, and is diagnosed in one out of every 500 Americans. For young athletes, hypertrophic cardiomyopathy can be fatal. Depending on the intensity of the sport, athletes could pass out or suddenly die because their heart cannot take it. Over a thousand genetic mutations have been linked to the disorder. As doctors increasingly look to genetic testing for diagnoses, experts say it is imperative to look at other minorities who may be affected by outdated information. Dr. Kenneth Offit, the chief of clinical genetics at New York’s Memorial Sloan Kettering Cancer Center, agrees. “From the vantage point of one who sits on several federal advisory bodies in the field of genetics, the importance of more extensive genomic sequencing in diverse populations cannot be over-emphazied,” said Offit. Previous genetic research did not test enough patients in any minority group to properly identify mutations linked illnesses. Kohane hopes to change that. “The cost of gene sequencing is now tiny, so I think we have the luxury to be able to get good representative control samples of our population, to make sure our studies are diversely controlled,” Kohane added.