el-Schahawi M, López de Munain A, Sarrazin A M, Shanske A L, Basirico M, Shanske S, DiMauro S
H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Diseases, Department of Neurology, Columbia-Presbyterian Medical Center, New York, NY 10032, USA.
Neurology. 1997 Feb;48(2):453-6. doi: 10.1212/wnl.48.2.453.
We describe two unrelated Spanish families with isolated sensorineural hearing loss. In both pedigrees, the deafness was transmitted maternally, which suggested a mitochondrial, DNA (mtDNA) defect. Within the same pedigree, some relatives showed aminoglycoside-induced deafness, whereas others were not exposed to aminoglycosides before the onset of hearing loss. Molecular genetic analysis in both families showed the A-to-G transition at nt 1555 (A1555G) in the mitochondrial 12S rRNA gene. In one pedigree, the mutation was homoplasmic; in the other, it was heteroplasmic. To assess the frequency of this mutation, we screened 42 patients of various ethnic backgrounds with isolated sensorineural hearing loss; none harbored the A1555G mutation. This is the first report of heteroplasmy in a family with isolated sensorineural deafness associated with the A1555G mutation.
我们描述了两个患有孤立性感音神经性听力损失的不相关西班牙家庭。在两个家系中，耳聋均通过母系遗传，这提示存在线粒体DNA（mtDNA）缺陷。在同一家系中，一些亲属表现出氨基糖苷类药物诱发的耳聋，而另一些亲属在听力损失发作前未接触过氨基糖苷类药物。对两个家庭进行的分子遗传学分析显示，线粒体12S rRNA基因第1555位核苷酸（A1555G）发生了A到G的转变。在一个家系中该突变是纯质的；在另一个家系中是异质的。为评估该突变的频率，我们对42名具有不同种族背景的孤立性感音神经性听力损失患者进行了筛查；均未携带A1555G突变。这是首次报道与A1555G突变相关的孤立性感音神经性耳聋家族中的异质性。
