Table 2.

Summary of clinical features of DFNB1 hearing impairment (HI).

Inheritance	Autosomal recessive (simplex and multiplex cases)
Age of onset	Mostly prelingual (not always congenital), but postlingual onset has also been reported
Evolution	Mostly stable, but progression has also been documented
Severity	Mild to profound
	Truncating mutations usually result in more severe phenotypes
Audiogram shape	Flat or down-sloping
Inner ear malformations	Prevalence typically lower than 10%
	Enlarged vestibular aqueduct, Mondini dysplasia
Vestibular function	Apparently normal, but a saccular dysfunction may go undetected (it can be revealed by VEMP or caloric testing)
Cochlear implantation	Good outcomes (improvement of speech perception skills and reading performance).
Phenotype of carriers	Loss of hearing in frequencies higher than 6 kHz
	Earlier onset of age-related hearing loss