Genetics of Deafness

Deafness is the most common sensory deficit in human populations with both genetic and environmental etiologies. It is estimated that it affects 1 in 1000 child births of which approximately 60% cases are attributed to genetic factors. Hearing impairment is clinically and genetically heterogeneous. Impaired auditory function can be the only clinical manifestation (non-syndromic forms of deafness) or can be associated with other symptoms or anomalies (syndromic forms of deafness). It has been estimated that at least 300 human protein-coding genes are involved in the hearing process. During the last decade, many deafness loci and the underlying genes have been identified at a rapid rate. Non-syndromic hearing loss transmitted as a recessive trait is the most frequent cause of hereditary deafness and often exhibits the most severe hearing phenotype. Recessively inherited diseases are more prevalent in populations where consanguineous marriages are common, like in Saudi Arabia. The same effect is observed for recessively inherited cases of deafness.

We are currently conducting a study to define the genetic basis of autosomal recessive deafness in the Saudi population. Families with profound congenital deafness and an autosomal recessive mode of inheritance will be identified from Saudi Arabia. The most common forms of hereditary deafness, their incidence and distribution in the Saudi population will be identified as the result from this study. The benefit of this study will provide knowledge and awareness through screening of carrier status and genetic counseling; overall having a major impact upon early intervention for and prevention of hereditary deafness.