Phelps P D, Reardon W, Pembrey M, Bellman S, Luxom L
Royal National Throat, Nose and Ear Hospital, London, UK.
Neuroradiology. 1991;33(4):326-30. doi: 10.1007/BF00587816.
The association of X-linked mixed deafness with stapes gusher has been recognized for 20 years, and imaging studies by polytomography have shown dilatation of the lateral end of the internal auditory meatus (IAM) in some cases. We have made genetic linkage studies in 7 pedigrees in whom deafness was inherited in an X-linked manner. All patients had a full range of audiometric and vestibular function tests. Thin section high resolution CT in two planes was used to assess the state of the middle and inner ears. We found a distinctive inner ear deformity in some of the deaf males characterised not only by a wide bulbous IAM but more importantly, by deficient or absent bone between the lateral end of the IAM and the basal turn of the cochlea. We believe that this results in a communication between the subarachnoid space in the IAM and the perilymph in the cochlea, leading to perilymphatic hydrops and a "gusher" if the stapes is disturbed. Moreover, some of the obligate female carriers seem to have a milder form of the same anomaly associated with slight hearing loss. Genetic studies on some of the deaf males with apparently normal inner ear anatomy suggest a different locus on the X chromosome and hence a different pathogenesis for the deafness.
X连锁混合性聋与镫骨井喷的关联已被认识20年，多层体层摄影术的影像学研究显示，部分病例内耳道（IAM）外侧端有扩张。我们对7个以X连锁方式遗传耳聋的家系进行了基因连锁研究。所有患者均进行了全面的听力测定和前庭功能测试。采用两个平面的薄层高分辨率CT评估中耳和内耳的状况。我们在部分耳聋男性中发现了一种独特的内耳畸形，其特征不仅在于IAM呈宽阔的球根状，更重要的是，在IAM外侧端与耳蜗底转之间缺乏骨质或骨质缺失。我们认为，这导致了IAM内的蛛网膜下腔与耳蜗内的外淋巴之间相通，若镫骨受到干扰，就会导致外淋巴积水和“井喷”。此外，一些必然的女性携带者似乎有相同异常的较轻形式，并伴有轻度听力损失。对一些内耳解剖结构明显正常的耳聋男性进行的基因研究表明，X染色体上存在不同的基因座，因此耳聋的发病机制也不同。
