表皮松解性掌跖角化病一家系KRT9基因突变检测

目的：检测一表皮松解性掌跖角化病(epidermolytic palmoplantar keratoderma,EPPK)家系中患者及其家族成员的KRT9基因突变。方法：收集该EPPK家系先证者及其家族成员临床资料,提取他们及100例无亲缘关系的健康对照外周血DNA,PCR扩增KRT9基因编码区的全部外显子及其侧翼序列,对产物直接测序,同时进行突变点的功能预测。结果：该家系所有患者的KRT9基因1号外显子第482位碱基均发生错义突变c.482A>G(p.Asn161Ser)。家系中未患病者及100名正常对照中均未发现此突变。SIFT和Polyphen-2软件预测c.482A>G(p.Asn161Ser)突变为有害变异位点。结论：KRT9基因的突变c.482A>G(p.Asn161Ser)可能是导致该家系发生表皮松解性掌跖角化病的原因。     

弥漫性表皮松解性掌跖角化病两家系突变分析

目的: 检测弥漫性表皮松解性掌跖角化病两家系中KRT9基因的突变情况。方法: 收集各家系患者的临床资料,抽取家系患者、正常人及200名健康志愿者外周血并提取DNA,采用聚合酶链式反应(PCR)扩增KRT9基因全部外显子并进行sanger测序。结果:在两个家系所有患者的KRT9基因1号外显子均检测到c．487C＞T 错义突变(p．163Ｒ＞W),家族未患病成员以及200名正常对照中未发现此突变。家系1中先证者的女儿和祖父除了掌跖角化过度外还出现了先天性指节垫和先天性指曲屈畸形,而家系2中所有患者并未出现该症状。结论: KRT9基因的c．487C＞T 错义突变是导致这两个表皮松解性掌跖角化病家系的遗传学病因,同一突变在不同家系或同一个家系的不同个体之间的临床表型存在差异。     

表皮松解性掌跖角皮症一家系KRT9基因新突变

目的:检测表皮松解性掌跖角皮症一家系患者角蛋白9(KRT9)基因突变。方法:收集家系成员的临床资料和血样,提取家系中4例患者和3名正常人及50名与本家系无关的正常对照外周血DNA,采用PCR技术扩增KRT9基因所有编码区并进行测序,分别检测家系中的突变情况。结果:该家系中所有患者均存在KRT9基因错义突变(c.484TC),导致第162位密码子由TCT(丝氨酸)转变为CCT(脯氨酸)(p.S162P),家系中3名正常个体和50名健康对照均未发现上述突变。结论:KRT9基因c.484TC错义突变是导致该家系发生表皮松解性掌跖角皮症的遗传基础。     

弥漫性掌跖角化病一家系角蛋白9基因检测

目的：检测弥漫性掌跖角化病一家系中的KRT9基因突变情况。方法：提取该家系中3例患者和3名家系正常成员及100名健康对照的外周血DNA,采取PCR扩增KRT9基因序列,ABI PRISM-3700测序仪检测KRT9基因突变情况。结果：该家系中3例患者存在KRT9基因上第487位C>T突变,而该家系的正常成员及健康对照未检测到突变。结论：KRT9基因基因突变C487T可能与本家系弥漫性掌跖角化病发病有关。     

表皮松解性掌跖角化症家系KRT9基因突变与临床表型分析

目的明确1个表皮松解性掌跖角化症(EPPK)家系的致病基因突变,为开展遗传咨询及产前诊断提供依据。方法收集家系内所有患者的临床表型资料,并采集血样提取基因组DNA,采用包含表皮松解性掌跖角化症相关基因的二代测序Panel结合Sanger测序验证的方法检测该家系的基因突变。结果该家系所有患者均在KRT9基因检测到c.1373TC(p.Leu458Pro)的杂合突变,该突变位于角蛋白9(K9)高度保守的螺旋2B区,该家系患者均未出现已有报道中检测到该突变患者存在的指节垫和先天性指屈曲症状。结论 KRT9基因c.1373TC(Leu458Pro)的杂合突变为本研究中EPPK的遗传学病因,同一突变在不同家系或不同个体之间的临床表型存在差异。     

以严重掌跖角化过度为主要表现的表皮松解性角化过度症一家系报告及基因突变分析

目的:报告一个以严重掌跖角化过度为主要表现的表皮松解性角化过度症(epidermolytic hyperkeratosis,EHK)家系,并检测其基因突变情况.方法:收集1个EHK家系的临床资料,取先证者皮损行组织病理检查.提取先证者及其亲属外周血DNA,应用PCR扩增角蛋白1(KRTl)、角蛋白10(KRT10)和角蛋白9(KRT9)基因编码区的全部外显子及其侧翼序列并行双向DNA测序,以100名健康志愿者外周血DNA作正常对照.结果:先证者皮损组织病理符合表皮松解性角化过度,所有患者的KRT1基因第1436位碱基发生T→C错义突变,导致其第479位氨基酸从异亮氨酸(Ⅰ)变为苏氨酸(T) (p.I479T).家系中未受累者和100名正常对照者未检测到该突变.在该家系所有成员中未检测到KRT10和KRT9基因突变.结论:KRT1基因的错义突变(p.I479T)可能是导致该家系患者临床表型的病因.     

表皮松解性掌跖角化病一家系KRT9基因突变检测及生物信息学分析

目的:检测表皮松解性掌跖角化病1家系KRT9基因突变情况并进行生物信息学分析。方法:提取家系患者、正常人及100名健康志愿者外周血DNA,采用聚合酶链式反应(PCR)扩增KRT9基因全部外显子并测序。与数据库比对测序结果,运用生物信息学软件进行突变型蛋白质结构及功能预测分析。结果:患者KRT9基因1号外显子内检测到一处c.487CT错义突变(p.163RW),家族未患病成员以及100名正常对照中未发现突变。生物信息学分析提示该突变会导致蛋白质二级结构和理化性质改变,功能分析提示该突变会改变蛋白质生物功能。结论:本家系检测到1个KRT9基因的热点突变,该突变对于疾病发生发展可能具有较大作用。     

KRT9基因突变所致表皮松解性掌跖角化病1例

报告KRT9基因突变所致表皮松解性掌跖角化病1例.患者男,中国籍,32岁,手足角化性斑块30余年.皮肤科检查:双侧掌跖面可见对称性弥漫性角化斑块,皮肤粗糙增厚,呈灰黄色.皮损组织病理:表皮明显角化过度,颗粒层棘层增厚,皮突延长,颗粒细胞变性,考虑掌跖角化病.基因全外显子组测序结果:KRT9基因外显子检测出c.487C＞...     

表皮松解性角化过度型鱼鳞病两家系基因突变研究

目的 探讨两个表皮松解性角化过度型鱼鳞病（EHK）家系的基因突变情况。 方法 收集两个EHK家系的临床资料,提取外周血DNA,通过PCR扩增角蛋白基因KRT1和KRT10编码区的全部外显子及其侧翼序列并测序,以表型正常家系成员及50例健康人作为对照。结果 发现两个家系中患者均存在KRT10基因突变,分别为KRT10的剪接位点突变c.1030-2A > G和错义突变c.467G > A,在家系中健康人及健康对照者未发现上述突变。结论 剪接位点突变c.1030-2A > G和错义突变c.467G > A,可能分别是导致这两个家系临床表型的原因。     

表皮松解掌跖角化症KRT9基因突变的研究进展

表皮松解性掌跖角化症(EPPK)是一种通常由位于17q12染色体上KRT9突变导致的常染色体显性遗传性皮肤病。本文综述了目前为止,EPPK家系中KRT9突变的类型及特点。通常认为KRT9基因突变热区位于螺旋结构的杆状功能域1A区和2B区。随着EPPK家系病例的不断积累,在K9的头部也已检出突变位点,不再局限于螺旋结构杆状结构域。     

一个表皮松解性掌跖角化病家系的KRT1基因突变分析

目的 探讨一个中国汉族人表皮松解性掌跖角化病(EPPK)家系的角蛋白基因KRT1、KRT9、KRT10突变情况.方法 收集1个EPPK家系的临床资料,提取外周血DNA,通过PCR扩增角蛋白KRT1、KRT9、KRT10基因编码区的全部外显子及其侧翼序列并测序,以表型正常家系成员及50例健康人为正常对照.结果 发现家系内6例患者均存在KRT1基因错义突变c.1436T>C,导致第479位的异亮氨酸被苏氨酸取代(I479T),在家系中6例正常人及50例对照者未发现上述突变.结论 错义突变KRTI的c.1436T>C可能为导致该家系临床表型的主要原因.本例为国内首次发现的KRT1突变引起的EPPK家系.

Abstract：

Objective To analyze the mutations in keratin 1 (KRT1), KRT9 and KRT10 genes in a Chinese family with epidermolytic palmoplantar keratoderma (EPPK). Methods Clinical data were collected from a family with EPPK. Genomic DNA was extracted from the peripheral blood of 12 family members, including 6 patients and 6 unaffected members, as well as from 50 unrelated normal human controls. PCR was performed to amplify all the exons and flanking sequences of KRT1, KRT9 and KRT10 genes followed by DNA sequencing.Results A missense mutation C.1436T > C was found in the highly conserved helix termination motif of KRT1 gene of all the patients, resulting in a substitution of isoleucine by threonine at position 479 of the KRT1 protein. No mutation was found in the unaffected members or unrelated controls. Conclusions The missense mutation C.1436T > C in K.RT1 gene is likely to be the main cause of the phenotype of EPPK in this family.This is the first report of a pedigree with KRT1 gene mutation-induced EPPK in China.     

Analysis of the KRT9 Gene in a Mexican Family with Epidermolytic Palmoplantar Keratoderma

Epidermolytic palmoplantar keratoderma (EPPK), an autosomal‐dominant genodermatosis, is the most frequently occurring hereditary palmoplantar keratoderma. EPPK is characterized by hyperkeratosis of the palms and soles. Approximately 90% of patients present with mutations in the KRT9 gene, which encodes for keratin 9. Many of these mutations are located within the highly conserved coil 1A region of the alpha‐helical rod domain of keratin 9, an important domain for keratin heterodimerization. The objective was to assess the clinical and molecular characteristics of a Mexican family with EPPK. The clinical characteristics of members of this family were analyzed. The KRT9 gene of affected members was polymerase chain reaction amplified from genomic DNA and sequenced. All affected members of the family had hyperkeratosis of the palms and soles with knuckle pads. The R163W mutation in the KRT9 gene was present in all affected individuals who were tested. Although R163W is the most frequent KRT9 mutation in patients with EPPK, only two families have been reported with knuckle pads associated with this mutation. Our findings indicate that knuckle pads can be associated with EPPK and the R163W mutation in a family with a genetic background different from that described here.     

A novel mutation of keratin 9 in a large Chinese family with epidermolytic palmoplantar keratoderma

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant inherited skin disorder characterized by diffuse yellow thickening of the skin of the palms and soles, sharply bordered with erythematous margins. Histologically and ultrastructurally, EPPK presents cytolysis of keratinocytes and abnormal aggregation of tonofilaments in the suprabasal layers of the epidermis. To date, 15 different mutations of the keratin 9 gene (KRT9) have been demonstrated to cause most cases of EPPK. OBJECTIVES: To identify the KRT9 mutation in a large Chinese family with EPPK. METHODS: Denaturing high-performance liquid chromatography (DHPLC), DNA sequencing and allele-specific polymerase chain reaction (AS-PCR) were used to screen exon 1 of the KRT9 gene for sequence variations. RESULTS: The DHPLC elution profiles of the DNA fragments amplified from the affected samples differed from those obtained from unaffected individuals, indicating that a sequence variation existed within the analysed fragment of KRT9. DNA sequencing revealed a novel insertion-deletion mutation in the exon 1 of KRT9, 497delAinsGGCT, resulting in the change of tyrosine(166) to tryptophan and leucine (Y166delinsWL). AS-PCR confirmed the mutation was not a common polymorphism. CONCLUSIONS: The results suggest the molecular basis of EPPK in this Chinese family and provide further evidence that mutations in the helix initiation motif of keratin 9 underlie Chinese EPPK.     

Atypical epidermolytic palmoplantar keratoderma presentation associated with a mutation in the keratin 1 gene

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis characterized by epidermolytic hyperkeratosis strictly confined to the palms and soles, and usually associated with mutations in the keratin K9 gene (KRT9). Mutations in the keratin K1 gene (KRT1) have been shown to underlie a variety of phenotypes typically involving generalized epidermolytic hyperkeratosis, but in some cases the phenotype can be more regionally restricted. OBJECTIVES: To identify the genetic defect in two unrelated families initially presenting with EPPK but where careful examination revealed hyperkeratosis extending on to the proximal wrist flexure. Methods Linkage analysis and DNA sequencing. RESULTS: We found that this phenotype is caused by a heterozygous missense mutation in the K1 gene, designated I479T. This mutation lies in the highly conserved helix termination motif of K1, previously shown to be important for keratin assembly and filament formation. In general, mutations in this region of keratins are associated with more severe disease phenotypes. However, K1 mutations in this region and the I479T mutation in particular have previously been associated with both severe and mild bullous congenital ichthyosiform erythroderma phenotypes. When further clinical enquiries were made, several affected individuals in the families studied here were found to have had transient flexural peeling and hyperkeratosis in the neonatal period. CONCLUSIONS: K1 mutations may underlie a phenotype closely resembling EPPK. A history of transient flexural peeling and hyperkeratosis in childhood and palmoplantar keratoderma which extends beyond the boundary of the palmoplantar margins may indicate a K1 mutation rather than a K9 defect. As K1 mutations are also associated with severe widespread phenotypes, with important implications for prognostic and genetic counselling, whole body examination is recommended for patients presenting with EPPK.     

Identification of the keratin K9 R162W mutation in patients of Italian origin with epidermolytic palmoplantar keratoderma

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant skin disorder characterized by hyperkeratosis of the palms and soles associated with histologic findings of hyperkeratosis and epidermolysis. Ultrastructurally, there is vacuolization of the cytoplasm and abnormal keratin filament network with tonofilament clumping. EPPK is caused by mutations in the keratin 9 gene (KRT9), which is expressed exclusively in suprabasal keratinocytes of palmoplantar epidermis. The mutation R162W is the most frequent keratin 9 alteration reported in patients from different geographical areas. We present three unrelated Italian families affected by EPPK in which we confirmed the presence of the R162W mutation, by RT-PCR analysis followed by sequencing of the KRT9 gene, in all affected members. The finding of the same mutation in all patients, together with the previous reports of the disease, strongly suggest that position 162 of the KRT9 gene represents a mutation "hot-spot", probably due to the peculiarity of the sequence.     

Keratin-9 gene mutation in epidermolytic palmoplantar keratoderma combined with knuckle pads in a large Chinese family

Epidermolytic plamoplantar keratoderma (EPPK) is an autosomal dominant inherited disease. It caused by mutations in the highly conserved coil 1A domain of the keratin 9 gene, KRT9 . We studied a four-generation family with EPPK combined with knuckle pads from Jiangsu province, China. In this study, a heterozygous nucleotide T→C transition at position 500 in exon 1 of KRT9 was detected, which resulted in a leucine to serine (L167S) change. We describe this mutation in a Chinese pedigree with EPPK with knuckle pads for the first time, demonstrating the prevalence of this mutation in diverse population.     

Mutation S233L in the 1B domain of keratin 1 causes epidermolytic palmoplantar keratoderma with "tonotubular" keratin

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis characterized by epidermolytic hyperkeratosis restricted to the palm and sole epidermis. The disorder is normally associated with dominant-negative mutations in the keratin 9 (K9) gene; however, a small number of cases have been reported where causative mutations were identified in the K1 gene. Here, we present two unrelated Dutch EPPK families with striking ultrastructural findings: tubular keratin structures in the cytoplasm of suprabasal cells. Similar structures were reported previously in a German EPPK family and were termed "tonotubular" keratin. After excluding the involvement of the K9 gene by complete sequencing, we identified a novel mutation, S233L, at the beginning of the 1B domain of K1 in both families. Protein expression studies in cultured cells indicated pathogenicity of this mutation. This is the first report of a genetic defect in this domain of K1. The unusual gain-of-function mutation points to a subtle role of the 1B domain in mediating filament-filament interactions with regular periodicity.