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

Hearing loss affects over 1.5 billion people worldwide, with around 430 million experiencing disabling loss. Non-syndromic cases often involve GJB2 and GJB6 pathogenic variants, yet their prevalence in Africans is unclear. This review synthesizes evidence on pathogenic variant prevalence and distribution among populations with NSHL. A systematic search was conducted across PubMed/MEDLINE, Google Scholar, DOAJ, AJOL, and the Cochrane Library to identify primary studies reporting GJB2 and GJB6 variants in African populations with NSHL, published from 2000. Inclusion criteria encompassed studies that focused on GJB2 and GJB6 pathogenic variant in individuals with NSHL. Data from eligible studies were extracted, analysed and synthesized to allow comparison across countries. A total of 716 records were identified from databases and grey literature, with 17 studies meeting inclusion criteria, published between 2001 and 2025. Research spanned several African countries, notably Cameroon, South Africa, Senegal, and Ghana. The prevalence of GJB2 and GJB6 pathogenic variants varied widely across populations. Pooled analysis estimated a 7% prevalence of GJB2 pathogenic variants among individuals with non-syndromic hearing loss (95% CI: 2.2–11.1; p = 0.004). GJB6 pathogenic variants were largely absent, except for two suspected pathogenic variants reported in one study. Higher contributions occurred in West Africa, while East and other regions showed minimal or no pathogenic variants. While GJB2 and GJB6 remain major genetic contributors to NSHL globally, their role in African populations is variable, underscoring the need for further research to identify additional genetic factors underlying NSHL and to develop population-specific molecular diagnostic strategies across diverse African populations.