<p>(A) Average threshold ± s.e.m. for wild-type (+/+) at 4 weeks (n = 3) and 10 weeks (n = 6), <i>Tur</i> heterozygous <i>(Tur/+)</i> at 10 weeks (n = 8) and homozygous ears (<i>Tur/Tur</i>) at 4 weeks (n = 5) and 10 weeks (n = 6) of age. Averages of 90 dB SPL were used for thresholds beyond the upper limit of the sound system. The <i>Tur/+</i> mice at 10 weeks of age had mild hearing loss in both ears (threshold shifted by 10–20 dB between 16 and 45 kHz), while <i>Tur/+</i> mice at 4 weeks of age (n = 5) had relatively normal hearing. However, all homozygous mice at 4 weeks of age had severe hearing loss (threshold shift by ~20–40 dB), while homozygous mice at 10 weeks of age had >35 dB loss between 5–11 kHz and >50 dB loss between 16–45 kHz.</p
