Chennupati Sri Kiran, Levi Jessica, Loftus Patricia, Jornlin Carly, Morlet Thierry, O'Reilly Robert C
St. Christopher's Hospital for Children, Division of Otolaryngology, 3601 A Street, Philadelphia, PA 19134, United States.
Int J Pediatr Otorhinolaryngol. 2011 Dec;75(12):1519-24. doi: 10.1016/j.ijporl.2011.08.019. Epub 2011 Oct 5.
At least 1-5 children per 1000 suffer from congenital hearing loss, and 50% of these cases can be attributed to genetic causes. It has been estimated that 1% of pre-lingual hearing loss is due to mutations in mitochondrial DNA. Previous literature reports audiometric data for few patients, usually less than 20 per study. The goal of this study was to characterize the hearing loss associated with mitochondrial mutations and determine whether previously characterized patterns of hearing loss in these patients (progressive, sensorineural, high frequency losses) are found in our population as well.
An IRB-approved retrospective chart review of the electronic medical records in the Nemours/Alfred I. dupont Hospital for Children system from January 2004 to October 2009 (a five-year period) was undertaken using ICD-9 codes 277.87 (mitochondrial disorder) and 359.89BA (mitochondrial myopathy). These 149 records were then evaluated for audiologic data, resulting in 26 charts with both a mitochondrial disorder and hearing evaluation.
Of 26 patients with known mitochondrial disorders and audiometric documentation, 15 (58%) had hearing loss, and 11 patients had normal hearing (42%). Ten patients had sensorineural hearing loss (38%), two patients had conductive hearing loss (7.7%), one patient had a mixed hearing loss (3.8%), and two patients had an as yet undefined hearing loss (ABR had not yet been performed at the time of this study) (7.7%).
In comparison with previous studies, generally including less than 20 patients, this is one of the largest collections of audiometric data on children with mitochondrial disorders. Unlike prior studies describing a progressive, sensorineural loss across all frequencies or mainly affecting high frequencies, the hearing loss in our patients was more variable including low frequency losses, mid-frequency losses, and conductive losses and was often not progressive or even improved. Our overall 38% rate of sensorineural hearing loss correlates well with previous case series; this study clearly justifies the use of routine audiometric screening in children with mitochondrial disorders, including use of ABR and OAEs as ASND can be seen in this population, as well as repeat testing over time to evaluate for progression.
每1000名儿童中至少有1 - 5名患有先天性听力损失，其中50%的病例可归因于遗传因素。据估计，1%的语前听力损失是由线粒体DNA突变引起的。以往文献报道的听力测定数据所涉及的患者较少，每项研究通常少于20例。本研究的目的是描述与线粒体突变相关的听力损失特征，并确定在我们的研究人群中是否也能发现这些患者先前已描述的听力损失模式（进行性、感音神经性、高频损失）。
使用ICD - 9编码277.87（线粒体疾病）和359.89BA（线粒体肌病），对2004年1月至2009年10月（五年期间）内Nemours/Alfred I. dupont儿童医院系统的电子病历进行了一项经机构审查委员会批准的回顾性图表审查。然后对这149份记录进行听力数据评估，最终得到26份既有线粒体疾病又有听力评估的图表。
在26例已知线粒体疾病且有听力测定记录的患者中，15例（58%）有听力损失，11例患者听力正常（42%）。10例患者有感音神经性听力损失（38%），2例患者有传导性听力损失（7.7%），1例患者有混合性听力损失（3.8%），2例患者有尚未明确的听力损失（在本研究时听觉脑干反应尚未进行）（7.7%）。
与以往通常纳入少于20例患者的研究相比，这是关于线粒体疾病儿童的最大规模听力测定数据收集之一。与先前描述的所有频率均为进行性感音神经性损失或主要影响高频的研究不同，我们患者的听力损失更为多样，包括低频损失、中频损失和传导性损失，且通常不是进行性的，甚至有所改善。我们总体38%的感音神经性听力损失发生率与先前的病例系列结果相关性良好；本研究明确证明了对线粒体疾病儿童进行常规听力测定筛查的必要性，包括使用听觉脑干反应和耳声发射，因为在该人群中可发现听觉稳态诱发电位，以及随时间进行重复测试以评估病情进展。
