A lack of diversity in medical research on the link between certain genetic traits and diseases are more likely to lead to incorrect diagnoses in black Americans and other minorities than in whites, according to a recent study published in The New England Journal of Medicine.
The study focused on the methodology for genetic testing for hypertrophic cardiomyopathy — a condition in which the heart's ventricle walls thicken, leading to arrhythmias and even sudden death. According to The New York Times, HCM can be caused by inherited mutations in one of 10 to 20 genes, and about one in 500 people in the U.S. have the disease.
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While genetic testing can help identify disease-causing mutations, researchers sought to find out the risk that mutations identified in genetic tests could be misclassified as disease. The study revealed that black people are more likely than whites to be mistakenly told they are at risk for HCM.
Using publicly accessible data, the researchers identified variants that were previously considered causal in HCM and that are overrepresented in the general population. They studied those variants within diverse populations and compared those findings to patient records at a leading genetic-testing lab, looking for occurrences of those variants over a 10-year period.
Numerous patients who were black or of unspecified ancestry were diagnosed as at risk for HCM based on the presence of genetic mutations that were misclassified as pathogenic when they were actually benign. The mutations most prevalent in the general population were significantly more common among black Americans than white Americans, though there was a weaker link between such mutations and HCM among black people.
Because most prior research and existing medical literature focused on the link between gene mutations and HCM in white patients, many black patients were misdiagnosed as at-risk for HCM.
"Simulations showed that the inclusion of even small numbers of black Americans in control cohorts probably would have prevented these misclassifications," the study authors wrote. "We identified methodological shortcomings that contributed to these errors in the medical literature."