Table 3.

Diagnostic Algorithm for Unknown Cause of Sensorineural Hearing Loss

History, Physical, and Audiological Evaluation
Clinical Test Results	Genetic Testing
Bilateral SNHL by appropriate hearing tests	GJB2, GJB6, mitochondrial DNA
Other common deafness genes
Bilateral enlarged vestibular aqueduct by CT scan	SLC26A4
Auditory neuropathy by OAE and ABR	OTOF
Mild to moderate SNHL at low frequencies, dominant	WFS1
Moderate to severe SNHL mid-frequency, recessive	TECTA
Progressive mild to severe HL with vestibular impairment, late onset	COCH
Characteristic Features of Other Less Common Nonsyndromic Deafness Genes
Autosomal dominant
Low frequency	DIAPH1
Auditory and peripheral neuropathy, erythrokeratodermia variabilis (no deafness)	GJB3, KCNQ4
Prelingual	GJB2, GJB6
Asymptomatic vestibular dysfunction	MYO7A
Middle frequency	COL11A2
Cochleosaccular degeneration	MYH9
Autosomal recessive
Prelingual or postlingual onset, reduced or absent vestibular function, retinitis pigmentosa	MYO7A
Prelingual or postlingual onset	TMPRSS3
Prelingual or postlingual onset	STRC
X-linked inheritance
Characteristic CT (dilated internal auditory canal with abnormal connection between subarachnoid space and cochlear endolymph)	POU3F4

Abbreviations: ABR, auditory brainstem response; CT, computed tomography; HL, hearing loss; OAE, otoacoustic emission; SNHL, sensorineural hearing loss.