Association of Racial/Ethnic Categories With the Ability of Genetic Tests to Detect a Cause of Cardiomyopathy.

Importance: Individuals of all races/ethnicities have a fundamental right to access health care and benefit from advances in science and medicine, including genetic testing. Objective: To determine whether detection rates for cardiomyopathy genetic testing differed between white people, Asian people, and underrepresented minorities (individuals of black, Hispanic, Native American, Alaskan Native, or Pacific Islander descent). Design, Setting, and Participants: We conducted a cross-sectional analysis of the genetic panel test results of 5729 probands who had a suspected diagnosis or family history of cardiomyopathy and who had been referred for testing between October 2003 and December 2017. Testing was performed at the Laboratory for Molecular Medicine at Partners Personalized Medicine in Cambridge, Massachusetts. Results were stratified into 3 categories of self-reported race/ethnicity: white, Asian, and underrepresented minorities. Main Outcomes and Measures: The primary outcome was whether a pathogenic or likely pathogenic variant was identified that explained the features or family history of cardiomyopathy. A secondary outcome was the number of test results that were inconclusive because of the presence of 1 or more variants of uncertain significance in the absence of an explanation for cardiomyopathy features or family history. Results: A total of 5729 probands were studied (of whom 3523 [61.5%] were male). Of these, 4539 (79.2%) were white, 348 (6.1%) were Asian individuals, and 842 (14.7%) were underrepresented minorities. Positive detection occurred in 1314 white individuals (29.0%) compared with 155 underrepresented minorities (18.4%; χ21 = 39.8; P < .001) and 87 Asian individuals (25.0%; χ21 = 2.5; P = .12). Inconclusive results were found in 1115 white individuals (24.6%) compared with 335 underrepresented minorities (39.8%; χ21 = 83.6; P < .001) and 136 Asian individuals (39.2%; χ21 = 35.8; P < .001). Conclusions and Relevance: These results show a significantly higher positive detection rate and a significantly lower rate of inconclusive results in white individuals in comparison with underrepresented minorities. This suggests greater clinical usefulness of genetic testing for cardiomyopathy in white persons in comparison with people of other racial/ethnic groups. This clear disparity warrants further study to understand the gaps in usefulness, which may derive from a lack of clinical testing and research in underrepresented minority populations, in the hopes of improving genetic testing outcomes for cardiomyopathy in nonwhite groups.