Racial and ethnic disparities in genetic testing for hearing loss: a systematic review and synthesis

Abstract

Racial/ethnic disparities in the diagnostic efficacy of genetic testing for hearing loss have been described. These disparities may relate to differences in variant classification between different racial/ethnic groups, which may, in turn, derive from disparate representation of these groups in the published literature. We sought to quantify racial/ethnic disparities in the published literature on the human genetics of hearing loss. We conducted a search of PubMed for articles describing single-gene, multiple-gene, or whole-exome sequencing for individuals with sensorineural hearing loss. Data on the included subjects, including race/ethnicity and/or region of origin, a number of subjects tested, and method of testing, were extracted. 1355 populations representing 311,092 subjects from 1165 studies were included. Overall, subjects of European and Asian ancestry were equivalently represented, but those of Latino American, African, and indigenous North American ancestry were significantly underrepresented; over 96% of all subjects in the published literature were European or Asian. Within populations, the majority of subjects derived from a small subset of countries. The observed disparity was greater for multiple-gene and whole-exome sequencing than for single-gene sequencing. These findings illustrate the large disparity in the published literature on the genetics of hearing loss, and demonstrate the need for increased representation of Latino American, African, and indigenous North American populations.

Fig. 1

Flowchart of a systematic review and population assignment

Fig. 2

Home country of the corresponding author. The number of studies with a corresponding author from each country is indicated. Darker blue indicates more studies (range as indicated in legend); yellow indicates no studies originating from that country

Fig. 3

Racial/ethnic distribution of published hearing-loss genetic testing data. The number of populations (left) and subjects (right) attributable to the indicated geographic ancestral groups is described for 1165 included studies, comprising 1355 populations and 311,092 subjects

Fig. 4

Countries/regions of origin for populations (A) and subjects (B) contributing to each geographic ancestral group

Fig. 5

Representation of geographic ancestral groups in published studies over time

Fig. 6

Representation of subjects from different geographic ancestral groups in published studies by genetic testing type