Consanguinity and deafness in Omani children

This study was based on a national retrospective analysis of 1400 questionnaires on the causes of deafness in Omani children, collected from 1986 to 2000. It was found that 70% of the deaf children were from parents of consanguineous marriages, and 30% from non-consanguineous unions. In those with consanguineous families 70.16% were first cousin marriages, 17.54% were second cousins, and 10.86% were from the same tribe. The proportion arising from first cousin marriages was higher than the background rate of first cousin marriages in Oman. In the total cohort, 45% had other family members with hearing loss. There was a greater chance of other relatives being affected in the consanguineous group as opposed to the non-consanguineous group (29.7% versus 15.3%). In most cases the affected relative was a deaf sibling (67.8%). We have demonstrated a higher rate of consanguinity amongst parents of deaf children in Oman and suggest this is associated with a higher frequency of autosomal recessive deafness in this...