Abstract:

Hearing loss is the most frequent sensory defect in humans. However, there are currently no consistent epidemiological data for hereditary hearing loss, except for severe and profound hear ing loss in early childhood. The prevalance for sensorineural hearing loss during childhood is estimated to be 1/1000, and approximately 60% is due to a genetic cause. Dozens of genes are thought to be responsible for the early onset of nonsyndromic hearing loss. Moreover, the mapping of genes for non-syndromic hearing loss has been difficult due to extreme genetic heterogeneity and the limitde audiological differentiation of hereditary hearing loss. The goal of this study is to describe the clinical characteristics of a family with an autosomal recessive mode of inheritance and briefly the result of linkage analysis. No additional symtoms and clinical findings other than sensorineural hearing loss of early onset Were found during ENT examination. The major characteristic of the family was presence of the hearing handicapped members born after consanguinuous marriages. The linkage analysis of this family\'s members by using microsatellite markers revealed that there was a defect on chromosome 2p22-23 (DFNB9). in conclusion, the phenotypic charcteristics must be noted in detail in familles with nonsyndromic hereditary hearing loss to enlighten the future molecular genetical investigations : nonsyndromic hereditary hearing loss to enlighten the future molecular genetical investigations.

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