Fig. 1

Audiograms of case 1,507,382 and 1,607,545. a The solid line represents the auditory thresholds measured when case 1,507,382 was 6 years old. The audiogram shows bilateral symmetrical severe sensorineural HL mainly affecting high frequencies, with residual hearing at low frequencies. Dashed lines indicate the results of auditory follow-up at seven, eight and nine years old, respectively. The pure tone threshold of this child increased by approximately 30–40 dB HL at 0.25 kHz–0.5 kHz and 10–20 dB HL at 1 kHz–8 kHz in the bilateral ears. b The solid line represents the auditory thresholds measured when case 1,607,545 was three years old, and the dashed lines display auditory thresholds when the child was four and six years old, respectively. The audiograms of the case 1,607,545 show bilateral residual hearing at low frequencies with progressive hearing loss at all frequencies. HL, hearing loss; dB, decibels; Hz, Hertz