Research across medical specialties found disparities in representative data among minority populations, especially Black patients. This study investigated these disparities specifically regarding genetic detection rates for inherited retinal diseases among Black and non-Hispanic White patients. Findings indicated that Black patients are less likely to receive a conclusive genetic diagnosis.
Current databases, such as gnomAD, primarily include data from individuals of European descent, but populations of African descent have comparatively more genetic variation that remains unspecified.
Understanding the genetic cause of an inherited retinal disease (IRD) is essential for confirming the diagnosis, predicting disease outcomes, providing genetic and reproductive counseling, and determining eligibility for approved or experimental treatments, the investigators explained in their JAMA Ophthalmology article. Because of the limited data on variants in non-European populations, IRD genes can be more difficult to classify in minority populations and often result in "variant of uncertain significance” labels. Black patients may therefore have limited opportunities to benefit from advancements in IRD therapeutics or may face challenges in inheritance counseling and reproductive decision-making.
This two-group comparison study analyzed retrospective data from the University of Michigan (UM) Kellogg Eye Center and Blueprint Genetics, spanning October 2013 to October 2022. The analysis included 572 patients from UM and 3,251 patients from Blueprint Genetics. Key variables included race, age, phenotype, and genetic testing panel size. Logistic regression and chi-square tests were employed to assess associations.
At UM, 38.9% of Black patients received a conclusive genetic diagnosis compared to 71% of White patients. Data from Blueprint Genetics revealed a similar trend, with detection rates of 44.4% for Black patients and 57.7% for White patients. Black race was independently associated with decreased odds of receiving a positive genetic test result, while older age and specific phenotypes, such as cone/cone-rod dystrophy, were also linked to reduced detection rates. The researchers noted that these detection rates were consistent with those in other studies, including detection rates for hereditary breast and prostate cancer, BRCA1 and BRCA2 genes, age-related macular degeneration-associated single-nucleotide variants, rod-cone dystrophies, and macular dystrophies.
The researchers emphasized that equitable access to genetic testing directly influences fairness in IRD clinical trials, as patients without a known genetic diagnosis have limited options for novel treatments. They stressed the importance of closely evaluating genetic detection rates among both majority and minority groups as new treatments emerge.
A full list of author disclosures can be found in the published research.