GJB2 variants found in 7% of African non-syndromic hearing loss cases in pooled review

The pooled estimate, reported by John Bukuru, Clarisse Musanabaganwa, Tolessa Muleta, George Otienno Mala, Elfiving Kristina and Leon Mutesa, comes from 17 primary studies published between 2001 and 2025, drawn from an initial pool of 716 records identified across databases and grey literature.

Both genes are well established contributors to non-syndromic hearing loss worldwide, and hearing loss itself affects more than 1.5 billion people globally, of whom around 430 million experience disabling loss. Despite this global picture, the authors note that the prevalence of these variants in African populations has remained unclear, motivating a structured synthesis of the existing primary literature.

Methodologically, the team conducted a systematic search across PubMed/MEDLINE, Google Scholar, DOAJ, AJOL and the Cochrane Library, targeting primary studies published from 2000 onwards that reported GJB2 and GJB6 pathogenic variants in individuals with NSHL in African populations. Studies were included if they focused specifically on these two genes in people with non-syndromic hearing loss. Data from eligible studies were then extracted, analysed and synthesized in a way that allowed comparison across countries, with the pooled analysis producing the headline prevalence estimate for GJB2.

The 17 included studies spanned several African countries, with research notably conducted in Cameroon, South Africa, Senegal and Ghana. Across these populations, the prevalence of GJB2 and GJB6 pathogenic variants varied widely. The pooled analysis placed the overall GJB2 pathogenic variant prevalence at 7% among individuals with non-syndromic hearing loss, though the wide confidence interval reflects substantial variation between the underlying studies rather than a single uniform rate.

GJB6 pathogenic variants told a different story. They were largely absent from the included studies, with the exception of two suspected pathogenic variants reported in a single study. This near-absence contrasts with the gene’s documented role in non-syndromic hearing loss in other parts of the world and suggests that, in African populations studied to date, GJB6 deletions or variants are not a common finding among NSHL cases.

Geographic patterns emerged from the synthesis. Higher contributions of GJB2 pathogenic variants were observed in West Africa, while East Africa and other regions showed minimal or no pathogenic variants in the included studies. The authors are careful to frame this as variation across populations rather than a change over time, and the pooled estimate should be read as a summary of the studies available, which differ in country, sample and method.

The review’s conclusion emphasizes that while GJB2 and GJB6 remain major genetic contributors to non-syndromic hearing loss globally, their role in African populations is variable. This variability, the authors argue, underscores the need for further research to identify additional genetic factors underlying NSHL in African populations and to develop population-specific molecular diagnostic strategies across the continent’s diverse populations.

As with any systematic review, the findings are bounded by the available evidence base. The 17 included studies cover a limited set of countries, and the pooled 7% figure carries a wide confidence interval, so the true prevalence in any given population may fall well above or below that point estimate. The article is published open access, with the version shared carrying a permanent DOI and noting that it is subject to further editorial edits before the final Version of Record.

The authors position the work as a foundation for broader genetic discovery and for diagnostic strategies tailored to specific African populations rather than imported wholesale from other regions.

Subject of Research: Prevalence and distribution of GJB2 and GJB6 pathogenic variants in non-syndromic hearing loss across African populations

Article Title: GJB2 and GJB6 pathogenic variants prevalence and variants distribution in non-syndromic hearing loss in African population: a systematic review and meta-analysis

Article References: Bukuru, J., Musanabaganwa, C., Muleta, T., Mala, G. O., Kristina, E., & Mutesa, L. (2026). GJB2 and GJB6 pathogenic variants prevalence and variants distribution in non-syndromic hearing loss in African population: a systematic review and meta-analysis. BMC Medical Genomics. https://doi.org/10.1186/s12920-026-02490-8

Image Credits: AI Generated

DOI: 10.1186/s12920-026-02490-8

Keywords: GJB2, GJB6, non-syndromic hearing loss, systematic review, meta-analysis, African populations, genetic variants, molecular diagnostics, BMC Medical Genomics, hearing loss prevalence, pathogenic, variants