Inheritance Pattern of Congenital Hearing Loss in Families Attending Audiology Clinics in Oyo State

Congenital hearing loss (CHL) is among the most common sensory deficits at birth, with genetic factors accounting for approximately 50 to 60 percent of cases in developed country estimates. In Nigeria, genetic epidemiology of CHL is poorly documented, particularly in the South West. This study investigated the inheritance pattern of congenital hearing loss in families attending audiology clinics at two tertiary hospitals in Oyo State. A retrospective and prospective case series design was adopted. Pedigree data were collected from 90 families with at least one member diagnosed with non-syndromic sensorineural hearing loss. Family history interviews, audiological assessments, and clinical records were reviewed. Inheritance pattern determination was based on pedigree analysis in accordance with standard Mendelian models. Autosomal recessive inheritance was the predominant pattern observed, followed by autosomal dominant and X-linked patterns in smaller proportions. Sporadic cases without identifiable familial aggregation also constituted a notable proportion. These results highlight the need for molecular genetic testing, particularly GJB2 gene sequencing (encoding connexin 26), to complement clinical pedigree analysis in Oyo State tertiary facilities. Keywords: congenital hearing loss, inheritance pattern, pedigree analysis, Oyo State, GJB2