Characteristic radiologic and audiologic markers. A.(a) In cases with enlarged vestibular aqueducts (arrow head) with or without an incomplete partition defect (arrow) SLC26A4 (with or without FOXI1 and KCNJ10) was tested. (b) In cases with bulbous dilatation at the distal end of the IAC and basal turn of the cochlea incompletely separated from the IAC (arrow) were tested for POU3F4. (c) Patients suspected of CHARGE syndrome were tested for CHD7. The most common associated inner ear anomaly is semicircular canal dysplasia (arrow). (d) Sequencing of the FGF3 gene was performed in patients with complete labyrinthine aplasia or cochlear hypoplasia (arrow). B.(a) Patients suspected of auditory neuropathy spectrum disorder were tested for the OTOF gene. The `otoacoustic emissions’ test is typically normal, whereas `auditory brainstem response’ is typically abnormal. No response was detected to 90 dB of click stimulus in the auditory brainstem response (upper panel). Signal-to-noise ratios of greater than 6 dB was shown in a specific frequency band in distortion product otoacoustic emissions (lower panel). (b) Audiograms showing ski slope type high frequency hearing loss with low frequency residual hearing initially and gradual deterioration with age. C. In cases of bilateral sensorineural hearing loss and a long EKG QT interval, KCNQ1/KCNE1 was sequenced.