A Study of Effect of Consanguinity on Cochlear Morphology in Patients with Congenital Bilateral Profound Sensorineural Hearing Loss

Abstract

Consanguinity has been considered as one of the risk factors predisposing to the development of congenital hearing loss. Effect of consanguinity on cochlear morphology has been subject of speculation, though many studies have provided insight into functional aspect of cochlea. This study was conducted to know the effect of consanguinity on cochlear morphology, if any. A prospective, observational study, including prelingually deaf children with bilateral profound sensorineural hearing loss who are registered as candidates for cochlear implantation at a tertiary care centre, was conducted. Seven children born out of consanguineous marriages and having bilateral congenital sensorineural hearing loss were imaged for their inner ears by MRI and various cochlear measurements were compared with that of seven control children born out of non-consanguineous marriages and who had congenital bilateral sensorineural hearing deafness. No statistically significant differences were noticed in the measurements of mean cochlear length, cross sectional diameter of cochlea at apex, middle turn and at basal turns; between children born of consanguineous and non-consanguineous marriages. Study revealed normal cochlear morphology in all the children born out of consanguineous marriages. Consanguinity, as a risk factor for development of sensorineural hearing loss, may not result in gross structural anomaly of cochlea. The genetic testing of these patients need not be extensive and can be limited to selective screening of genes responsible for functioning of cochlea rather than its anatomical development.