Casano R A, Bykhovskaya Y, Johnson D F, Hamon M, Torricelli F, Bigozzi M, Fischel-Ghodsian N
Ahmanson Department of Pediatrics, Steven Spielberg Pediatric Research Center, Cedars-Sinai Medical Center and UCLA School of Medicine, Los Angeles, California 90048, USA.
Am J Med Genet. 1998 Oct 12;79(5):388-91.
Six Italian families with familial nonsyndromic hearing loss consistent with a maternal pattern of inheritance were analyzed for mitochondrial mutations. The three known mitochondrial mutations associated with nonsyndromic hearing loss were investigated by polymerase chain reaction amplification, followed by restriction fragment length analysis or DNA sequencing. The A7445G mutation and C7472 insertion were not present in either of the families, but the A1555G mutation in the 12S rRNA gene was identified in homoplasmic form in two of the families. In one of the families the onset of hearing loss is congenital, while in the other it starts later in life. The families are from different regions of Italy, and mitochondrial haplotype analysis showed that the mutation arose independently in these two families. This suggests that the A1555G mutation may not be an uncommon cause of hearing loss in Italians, and is clinically important because maternal hearing relatives of patients with the A1555G mutation are at risk for aminoglycoside induced deafness. We discuss potential reasons for the normal phenotype in some relatives with the mutation, and the different onset of hearing loss in the two families.
对六个患有符合母系遗传模式的家族性非综合征性听力损失的意大利家族进行了线粒体突变分析。通过聚合酶链反应扩增，随后进行限制性片段长度分析或DNA测序，研究了与非综合征性听力损失相关的三种已知线粒体突变。A7445G突变和C7472插入在任何一个家族中均未出现，但在两个家族中以纯质形式鉴定出12S rRNA基因中的A1555G突变。在其中一个家族中，听力损失的发病是先天性的，而在另一个家族中则在生命后期开始。这些家族来自意大利的不同地区，线粒体单倍型分析表明该突变在这两个家族中独立出现。这表明A1555G突变可能是意大利人听力损失的一个常见原因，并且在临床上很重要，因为携带A1555G突变患者的母系听力亲属有氨基糖苷类药物诱发耳聋的风险。我们讨论了一些携带该突变亲属表现正常的潜在原因，以及两个家族中听力损失发病不同的情况。
