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

OBJECTIVES: This study aims to define the relative risk of development of hearing loss in offspring of consanguineous marriages. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: There was 76% increased risk for consanguineous marriage progeny to develop SNHL when compared to non consanguineous progeny.

Vestibular-evoked myogenic potentials and subjective visual vertical testing in patients with vitamin D deficiency/insufficiency.

Otolith function in subjects with vitamin D deficiency/insufficiency is investigated through vestibular-evoked myogenic potentials (VEMP) and subjective visual vertical (SVV) testing. The study group included 62 patients with vitamin D deficiency/insufficiency (30 females, 32 males), with age range 24-56 years (40.6 ± 9.1). The control group included 44 healthy volunteers of similar age and gender distribution. The entire study group had: (1) serum level of 25-hydroxyvitamin D <30 ng/ml; (2) normal bone mineral density as indicated by dual-energy X-ray absorptiometry with T-score >-1; (3) normal middle ear function; (4) Age is ≤60 years. All subjects enrolled in the current study underwent audiovestibular evaluation consisting of pure-tone audiometry, immittancemetry, cervical VEMP (cVEMP), ocular VEMP (oVEMP), and SSV. The entire control group had normal cVEMP, two subjects had abnormal oVEMP. Thirty-three subjects (53%) in the study group had abnormal oVEMP and 31 subjects (50%) had abnormal cVEMP. Forty-one (66%) had abnormal VEMP when abnormal VEMP was considered as either abnormal oVEMP or cVEMP. The entire control and study groups had normal SSV test results. Vitamin D deficiency may be associated with development of otolith dysfunction affecting both the utricle and saccule. This was suggested by the high prevalence of abnormal ocular vestibular-evoked myogenic potentials (oVEMP) and cervical vestibular-evoked myogenic potentials (cVEMP) in the study group.