Yang Mei-Hui, Lee Julia Yu-Yun, Lin Jeng-Hsien, Chao Sheau-Chiou
Graduate Institute of Biotechnology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.
J Formos Med Assoc. 2003 Jul;102(7):492-6.
Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant hereditary disorder of keratinization. Recent molecular studies have shown that EPPK is caused by mutations in keratin 9 gene (K9). We report 2 unrelated sporadic cases of EPPK in Taiwanese, confirmed by histopathology and electron microscopy. A de novo mutation with a C to T transition at the first nucleotide of codon 162 in K9 was detected in both patients, but not in their parents. The mutation is expected to result in an arginine to tryptophan substitution (R162W) in the beginning region of the alpha-helical 1A domain of K9. Mutations in this region could disrupt keratin filament assembly, leading to degeneration or cytolysis of keratinocytes. Mutations of this arginine codon (R162W, R162Q) are common in pedigrees with EPPK. Our mutation analysis suggests that codon 162 in K9 gene is an important hot spot for mutation in EPPK.
表皮松解性掌跖角化病（EPPK）是一种常染色体显性遗传性角化障碍疾病。最近的分子研究表明，EPPK是由角蛋白9基因（K9）突变引起的。我们报告了2例台湾地区散发的、无血缘关系的EPPK病例，经组织病理学和电子显微镜检查确诊。在两名患者中均检测到K9基因第162密码子第一个核苷酸处发生C到T的从头突变，但其父母未检测到该突变。预计该突变会导致K9基因α螺旋1A结构域起始区域的精氨酸被色氨酸替代（R162W）。该区域的突变可能会破坏角蛋白丝组装，导致角质形成细胞变性或溶解。这种精氨酸密码子的突变（R162W、R162Q）在EPPK家系中很常见。我们的突变分析表明，K9基因中的第162密码子是EPPK突变的一个重要热点。
