The risk ratio for development of hereditary sensorineural hearing loss in consanguineous marriage offspring

This study aims to define the relative risk of development of hearing loss in offspring of consanguineous marriages.

This is a retrospective case-control study conducted in a tertiary referral center in Jeddah, KSA. The study group included 1600 probands (848 males, 752 females), with age range 0.5-12 years (6.6 ± 3.6). The study group comprised of two equal, age and sex matched subgroups; Hearing Loss (HL) group and Normal Hearing (NH) group. The children included in the HL group should have idiopathic or non syndromic genetic sensorineural hearing loss.

The HL Group comprised 800 children with variable degrees of sensorineural hearing loss. Profound and severe degrees of hearing loss were the most prevalent degrees (P <0.05%). The prevalence of consanguineous marriage offspring in the NH group was 42.5%, while in the HL group it was 68.9% (P < 0.05). The differences between both study subgroups regarding the distribution of different degrees of parental consanguinity (first, second, double first, and first once removed cousins) were insignificant (P > 0.05). The relative risk and 95% confidence interval (RR, 95% CI) for development of hearing loss in offspring of consanguineous marriage was 1.76 (95% CI 1.57-1.97, P < 0.001).

There was 76% increased risk for consanguineous marriage progeny to develop SNHL when compared to non consanguineous progeny.