Ⅱ型先天性厚甲症一家系KRT基因突变检测

目的:检测先天性厚甲症一家系中KRT6b和KRT17基因突变位点。方法:提取先证者、其父母(母亲为患者,父亲正常人)及100名正常对照者外周静脉血DNA,PCR技术扩增KRT6b和KRT17基因编码序列,Sanger测序法对PCR扩增产物进行测序。结果:先症者及其母亲在KRT17基因1号外显子上存在错义突变(c.275AG),KRT6b基因不存在任何突变。先证者父亲及100名正常对照者中未检测到任何突变。结论:此家系患者是由于KRT17基因突变(c.275AG,p.Asn92Ser)所致。     

单纯型大疱性表皮松解症患儿的角蛋白5基因突变研究

目的：对1例单纯型大疱性表皮松解症(EBS)患儿及其家系进行基因突变检测和致病性分析。方法：应用高通量二代测序技术捕获目标序列,对患儿进行全外显子组测序。发现致病位点后,应用Sanger测序法进行家系验证,查阅人类基因突变数据库(HGMD),运用生物信息学蛋白功能预测软件,分析变异位点的致病性。结果：患儿角蛋白5(KRT5)基因的第一外显子检出杂合变异c.536T>C(p.F179S),该变异造成KRT5蛋白的第179位氨基酸改变,患儿父母均未检测到相同突变。结论：患儿KRT5基因的杂合变异c.536T>C(p.F179S)为新发致病性变异,导致患儿KRT5缺陷,进而引发疱疹样型EBS(DM-EBS)。该变异位点在国内未见报道,扩大了我国人群KRT5的基因突变谱,为家系的遗传咨询和产前诊断提供依据。     

有汗型外胚层发育不良家系调查及基因突变研究

目的：报告1例有汗型外胚层发育不良家系的致病基因突变。方法：收集患者临床资料,提取先证者及其部分亲属外周血DNA进行全外显子测序,Sanger测序验证致病突变。结果：先证者GJB6基因编码区发生杂合无义突变c.263C>T(p.A88V),突变来自其母亲。在其4位患病亲属中检测到相同突变,在其父亲（正常人）中未检测到此突变。结论：GJB6基因c.263C>T(p.A88V)杂合突变是该家系的遗传学致病因素。     

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二家系基因突变检测

目的：检测表皮松解性掌跖角化病二家系患者致病基因。方法：收集二家系资料,提取二家系成员及100名（无亲缘关系）正常对照血样DNA,采取聚合酶链反应技术对KRT1、KRT9和KRT16基因进行扩增,并对其产物进行测序。结果：家系1先证者中检测到 KRT1基因突变c.598T>C（p.F200L）。家系2三例患者中检测到KRT9基因含杂合突变c.488G>A（p.R163Q）。而家系正常成员及家系外无亲缘关系的100名正常对照中均不存在以上突变。结论：本研究表皮松解性掌跖角化病二家系发病与KRT1、KRT9基因突变有关,且KRT1基因突变p.F200L为国内首次报道。     

先天性厚甲症一家系的KRT基因突变分析

目的检测一先天性厚甲症(PC)家系的致病基因KRT6a、KRT6b、KRT16、KRT17,以期找到其可能的致病突变。方法常规收集该家系成员外周静脉血,同时采集同地区100名健康自愿者外周血作为正常对照。分别提取DNA,运用聚合酶链反应(PCR)扩增基因KRT6a、KRT6b、KRT16、KRT17的全部外显子及其侧翼内含子序列,产物纯化后直接行DNA测序,比对分析其基因突变位点和类型。结果 PC患者KRT6a基因第1号外显子存在错义突变c.521TC(p.Phe174Ser),而正常家系成员和正常对照组均无此突变,KRT6b、KRT16和KRT17基因也未发现致病突变。结论该PC家系的患者存在一个错义突变——KRT6a基因第1号外显子c.521TC(p.Phe174Ser)。该突变是导致PC发病的分子基础。     

多发性皮脂腺囊肿一家系角蛋白17基因突变检测

目的 研究多发性皮脂腺囊肿一家系中角蛋白17的基因突变情况。方法 收集1个多发性皮脂腺囊肿家系中3例患者及3例表型正常者和50例无亲缘关系健康个体的外周血标本,采用PCR结合DNA直接测序检测角蛋白17基因突变。结果 该家系患者角蛋白17基因上第428位碱基胞嘧啶（C）突变为胸腺嘧啶（T）,使角蛋白17基因的第1号外显子94位密码子由CGC突变成TGC,第94位精氨酸被组氨酸取代,即R94C突变,而该家系的正常人对照及无亲缘关系健康个体不存在此突变。结论 本多发性皮脂腺囊肿家系患者角蛋白17基因存在错义突变（428C→T）,这可能是导致多发性皮脂腺囊肿发病的分子机制之一。     

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。     

角蛋白14突变导致Dowling-Meara亚型单纯型大疱性表皮松解症伴色素沉着

目的:检测Dowling-Meara 亚型单纯型大疱性表皮松解症(DM-EBS)伴色素沉着一家系的基因突变.方法:收集DMEBS患儿临床资料;取皮损行透射电镜检查;应用PCR及DNA 直接测序的方法,检测该家系成员角蛋白(KRT)5 和KRT14 基因的全部编码序列,并与正常序列进行对比.结果:透射电镜检查可见基底细胞下部裂隙形成,张力微丝呈团块状.患儿KRT14基因第1 号外显子中的第373 位碱基发生C→T 杂合突变(c.C373 T),导致其编码的KRT14 1A 螺旋段第125 位氨基酸发生错义突变(p.R125C),患儿父母未发现该突变.结论:KRT14 基因的R125C 突变可能为引起该患儿临床表型的病因,推测认为该突变不仅可引起表皮松解,还可造成皮肤色素沉着.     

有汗性外胚层发育不良一家系基因突变

目的 探讨有汗性外胚层发育不良家系的基因突变及突变类型，为建立本病的基因诊断与遗传咨询提供依据。方法 PCR及Sanger测序技术对有汗性外胚层发育不良家系先证者GJB6基因外显子进行突变鉴定，对可疑的变异位点， Sanger测序检测家系其他成员该位点变异情况。结果 基因检测结果表明，家系先症者GJB6基因错义突变c.31G〉A，该突变导致连接蛋白-30（connexin-30, CX-30）第11位氨基酸由甘氨酸变成精氨酸（p.G11R）。家系的患者均携带此变异，而家系表型正常的个体不携带此变异。结论 GJB6基因c.31G〉A（p.G11R）突变是该有汗性外胚层发育不良家系致病基因突变。     

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.     

A new keratin 5 mutation (K199T) in a family with Weber-Cockayne epidermolysis bullosa simplex

A new missense mutation in the keratin 5 gene (KRT5) in a Chinese family with Weber-Cockayne type epidermolysis bullosa simplex is reported. Direct sequencing identified a heterozygous A --> C substitution at nucleotide 596 altering codon 199 of KRT5 from lysine to threonine in all affected family members, but not in the unaffected family members or in 50 unrelated control samples. The mutation is designated K199T. This mutated lysine residue is sited within the 1A domain of keratin 5 and is highly conserved among all type II keratins. The mutation may perturb the alignment of tonofilaments and, as a consequence, result in skin fragility and blistering.     

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。     

Generalized bullae in a young girl with KRT6A-related pachyonychia congenita

Pachyonychia congenita (PC) is a rare genodermatosis showing heterogeneity with five causative keratin genes (KRT6A, KRT6B, KRT6C, KRT16, or KRT17). Clinically, PC is characterized by hypertrophic onychodystrophy, painful palmoplantar keratoderma, oral leukokeratosis, and follicular hyperkeratosis. We describe an atypical case of PC in a young Chinese girl presenting with generalized bullae and identified a recurrent heterozygous missense mutation c.1406T > C (p.Leu469Pro) in KRT6A. This suggests that bullae may represent an important feature of KRT6A-related PC.     

A large mutational study in pachyonychia congenita

Pachyonychia congenita (PC) is a rare autosomal dominant skin disorder characterized predominantly by nail dystrophy and painful palmoplantar keratoderma. Additional clinical features include oral leukokeratosis, follicular keratosis, and cysts (steatocysts and pilosebaceous cysts). PC is due to heterozygous mutations in one of four keratin genes, namely, KRT6A, KRT6B, KRT16, or KRT17. Here, we report genetic analysis of 90 new families with PC in which we identified mutations in KRT6A, KRT6B, KRT16, or KRT17, thereby confirming their clinical diagnosis. A total of 21 previously unreported and 22 known mutations were found. Approximately half of the kindreds had mutations in KRT6A (52%), 28% had mutations in KRT16, 17% in KRT17, and 3% of families had mutations in KRT6B. Most of the mutations were heterozygous missense or small in-frame insertion/deletion mutations occurring within one of the helix boundary motif regions of the keratin polypeptide. More unusual mutations included heterozygous splice site mutations, nonsense mutations, and a 1-bp insertion mutation, leading to a frameshift and premature termination codon. This study, together with previously reported mutations, identifies mutation hotspot codons that may be useful in the development of personalized medicine for PC.     

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。     

Mice expressing a mutant Krt75 (K6hf) allele develop hair and nail defects resembling pachyonychia congenita

KRT75 (formerly known as K6hf) is one of the isoforms of the keratin 6 (KRT6) family located within the type II cytokeratin gene cluster on chromosome 12 of humans and chromosome 15 of mice. KRT75 is expressed in the companion layer and upper germinative matrix region of the hair follicle, the medulla of the hair shaft, and in epithelia of the nail bed. Dominant mutations in members of the KRT6 family, such as in KRT6A and KRT6B cause pachyonychia congenita (PC) -1 and -2, respectively. To determine the function of KRT75 in skin appendages, we introduced a dominant mutation into a highly conserved residue in the helix initiation peptide of Krt75. Mice expressing this mutant form of Krt75 developed hair and nail defects resembling PC. This mouse model provides in vivo evidence for the critical roles played by Krt75 in maintaining hair shaft and nail integrity. Furthermore, the phenotypes observed in our mutant Krt75 mice suggest that KRT75 may be a candidate gene for screening PC patients who do not exhibit obvious mutations in KRT6A, KRT6B, KRT16, or KRT17, especially those with extensive hair involvement.     

一对先天性大疱性鱼鳞病样红皮病双胞胎患者表型与角蛋白1基因突变研究

目的 检测先天性大疱性鱼鳞病样红皮病双胞胎患者角蛋白1、10（KRT1、KRT10）基因突变情况,探讨致病基因与表型间的关系。方法 收集1对先天性大疱性鱼鳞病样红皮病双胞胎患者及家族成员的临床资料。提取该双胞胎患者及其兄、父、母的外周血DNA,PCR扩增KRT1和KRT10基因编码区全部外显子及其侧翼序列并测序,以100例健康人作为对照。结果 先证者男,11岁,全身皮肤反复起水疱、肥厚伴脱屑11年;其双胞胎弟弟有类似皮损。2例患者KRT1基因1号内含子第1位碱基发生突变（c.591 + 1G > A）,而家系中3例正常成员和无亲缘关系的100例健康对照均未发现该突变。结论 KRT1基因1号内含子第1位碱基突变（c.591 + 1G > A）可能为引起该双胞胎患者临床表型的病因。