Brucker-Davis F, Skarulis M C, Pikus A, Ishizawar D, Mastroianni M A, Koby M, Weintraub B D
Molecular and Cellular Endocrinology Branch, National Institute of Diabetes, Digestive, and Kidney Disease, National Institutes of Health, Bethesda, Maryland 20892-1758, USA.
J Clin Endocrinol Metab. 1996 Aug;81(8):2768-72. doi: 10.1210/jcem.81.8.8768826.
Hearing impairment was anecdotally reported in resistance to thyroid hormone (RTH), a condition caused by mutations in the beta-thyroid hormone receptor (beta TR) gene. Because of its ontogenic distribution in the cochlea, the beta TR may have a pivotal role in the development of auditory function. To assess the prevalence and mechanisms of hearing impairment in RTH, 82 RTH-positive (RTH+) patients and 55 unaffected relatives (RTH-) underwent systematic audiological examination, including puretone and speech reception thresholds, and tests studying middle ear (tympanometry and acoustic reflexes), cochlear (otoacoustic emissions), and retrocochlear integrity (brain stem auditory evoked potentials). Significant hearing loss was present in 21% of RTH+ patients vs. none in RTH- patients. More RTH+ patients had abnormal tympanometry (34% vs. 12%) and abnormal acoustic reflexes (39% vs. 19%). Isolated conductive deficit was found in 7 of 17 RTH+ patients with hearing loss, isolated sensorineural deficit in 7 cases, and mixed deficit in 3 cases. Cochlear dysfunction was found in 50% of all RTH+ patients, with or without hearing loss. Retrocochlear function was normal. No morphological cochlear abnormalities were detected on computed tomography of the temporal bone. In conclusion, hearing loss is a significant problem in RTH, with an equal frequency of conductive (probably related to the frequent ear infections) and sensorineural deficits. Abnormal otoacoustic emissions suggest that the mutant beta TR has a specific negative impact on cochlear function.
有传闻称，甲状腺激素抵抗（RTH）患者存在听力障碍，该病由β-甲状腺激素受体（βTR）基因突变引起。由于βTR在耳蜗中的个体发生分布，它可能在听觉功能发育中起关键作用。为评估RTH患者听力障碍的患病率及机制，对82例RTH阳性（RTH+）患者和55例未受影响的亲属（RTH-）进行了系统的听力学检查，包括纯音和言语接受阈值，以及研究中耳（鼓室导抗图和声反射）、耳蜗（耳声发射）和蜗后完整性（脑干听觉诱发电位）的测试。21%的RTH+患者存在明显听力损失，而RTH-患者中无一例出现。更多的RTH+患者鼓室导抗图异常（34%对12%）和声反射异常（39%对19%）。17例有听力损失的RTH+患者中，7例为单纯传导性缺陷，7例为单纯感音神经性缺陷，3例为混合性缺陷。所有RTH+患者中有50%存在耳蜗功能障碍，无论有无听力损失。蜗后功能正常。颞骨计算机断层扫描未发现耳蜗形态学异常。总之，听力损失是RTH中的一个重要问题，传导性（可能与频繁耳部感染有关）和感音神经性缺陷的发生率相同。异常耳声发射表明突变的βTR对耳蜗功能有特定的负面影响。
