Clinical and genetic features in a Chinese pedigree with autosomal dominant auditory neuropathy.

BACKGROUND

A variety of processes and etiologies are thought to be involved in the pathophysiology of auditory neuropathy (AN). However, little is known about the clinical and molecular characteristics of hereditary AN.

OBJECTIVE

To explore the clinical and genetic findings of a Chinese family with AN.

METHODS

Seven patients in three consecutive generations of the pedigree were selected. Detailed history collection, physical examination, and audiological evaluations including pure-tone audiometry, acoustic immittance, auditory brainstem responses, cochlear microphonics, and evoked otoacoustic emissions, and mitochondrial DNA analysis were performed.

RESULTS

All subjects involved are offspring of a female ancestor in the pedigree. In 6 of them, the hearing impairment started before the age of 9. Audiograms showed bilateral, symmetric, and profound deafness. Other audiological examinations revealed absent acoustic reflexes and auditory brainstem responses, and preserved evoked otoacoustic emissions and cochlear microphonics. One subject was characterized by normal audiological findings except high-frequency hearing loss with later onset. Hearing deterioration was found in 2 subjects who were followed for 26 months. Physical examination and mitochondrial DNA analysis yielded normal results.

CONCLUSIONS

Clinical features in the pedigree are consistent with type II AN. Pedigree analysis and molecular findings indicate an autosomal dominant inheritance.