We initiated a clinical and genetic linkage study on members of a large Venezuelan family with hereditary hearing loss. A medical history and a physical examination were performed on 30 family members. Audiometry was carried out in 25 subjects, and in 2 additional children auditory brainstem responses were obtained. Additional testing (site-of-lesion, electronystagmography and computed tomography) was also obtained in a few subjects. DNA was extracted from blood samples from 25 family members. The type of deafness in this family is neurosensorial, non-syndromic and postlingual. The average age of onset of deafness is 7 years and there is a rapid progression leading to profound deafness. Deafness is possibly of cochlear origin and there is no associated vestibular pathology. Analysis of the pedigree discloses a maternal pattern of inheritance with a significant female predominance, compatible with a mutation of the mitochondrial DNA. The molecular DNA analysis for the known mitochondrial mutations are discussed.
- Hereditary diseases
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