Department of Otolaryngology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Japan.
J Hum Genet. 2010 Dec;55(12):796-800. doi: 10.1038/jhg.2010.115. Epub 2010 Sep 16.
Usher syndrome (USH) is an autosomal recessive disorder characterized by retinitis pigmentosa and hearing loss. USH type 1 (USH1), the second common type of USH, is frequently caused by MYO7A and CDH23 mutations, accounting for 70-80% of the cases among various ethnicities, including Caucasians, Africans and Asians. However, there have been no reports of mutation analysis for any responsible genes for USH1 in Japanese patients. This study describes the first mutation analysis of MYO7A and CDH23 in Japanese USH1 patients. Five mutations (three in MYO7A and two in CDH23) were identified in four of five unrelated patients. Of these mutations, two were novel. One of them, p.Tyr1942SerfsX23 in CDH23, was a large deletion causing the loss of 3 exons. This is the first large deletion to be found in CDH23. The incidence of the MYO7A and CDH23 mutations in the study population was 80%, which is consistent with previous findings. Therefore, mutation screening for these genes is expected to be a highly sensitive method for diagnosing USH1 among the Japanese.
先天性进行性视网膜色素变性伴耳聋综合征（Usher 综合征，USH）是一种常染色体隐性遗传病，以视网膜色素变性和感音神经性聋为主要特征。USH1 型是 USH 第二常见的类型，常由 MYO7A 和 CDH23 基因突变引起，在不同种族人群中占比 70%-80%，包括白种人、黑人和亚洲人。然而，目前尚未有日本患者 USH1 相关基因的突变分析报道。本研究对 5 例日本 USH1 患者进行了 MYO7A 和 CDH23 的基因突变分析。在 5 例非相关患者中发现了 5 个突变（3 个 MYO7A 和 2 个 CDH23）。其中 2 个为新突变，包括 CDH23 上的 p.Tyr1942SerfsX23，这是一个导致 3 个外显子缺失的大片段缺失突变，是 CDH23 中首次发现的大片段缺失。本研究人群中 MYO7A 和 CDH23 突变的发生率为 80%，与既往研究结果一致。因此，对这些基因进行突变筛查有望成为日本人群 USH1 诊断的一种高度敏感的方法。
