Figure 2. .

Pure-tone air-conduction averages (0.5, 1, 2, and 4 kHz) for the better-hearing ears of seven of the eight DFNB49-affected families. The X-axis is age, and the Y-axis is the average decibel (dBHL) at which the threshold of hearing is detected. There is inter- and intrafamilial variability in the severity of hearing loss due to recessive mutations of TRIC, which may be caused by genetic modifiers and/or environmental factors. For control subjects and normal-hearing members of families, hearing thresholds measured in ambient-noise conditions were 25–30 dBHL.