点状掌跖角化病3家系AAGAB致病基因突变位点检测

目的:检测点状掌跖角化病家系中AAGAB基因的突变。方法:分别对来自3个家系的3例患者应用聚合酶链反应(PCR)扩增外周血基因组AAGAB基因的10个外显子及邻近内含子区域,对其产物直接测序和序列分析。结果:3例患者的AAGAB基因编码区均未发现突变位点。结论:AAGAB基因与本研究中的点状掌跖角化病患者发病无关联,提示可能存在其它致病基因。     

角化性皮肤病

20090162 β-Catenin在角化性皮肤病与非黑素细胞性皮肤肿瘤中的表达;20090163点状掌跖角化病一家系;20090164一例表皮松解性掌跖角化病家系的角蛋白9基因突变检测研究;20090165副肿瘤性肢端角化病误诊1例     

中国汉族人5家系40例点状掌跖角化病临床及遗传特点分析

目的了解中国汉族人点状掌跖角化病(punctate,palmop lantar keratoderm a)的临床表型和遗传学特点。方法对收集的1例点状掌跖角化病家系进行系统的临床表型和遗传学特点的分析,并将结果与国内报道的其他4例点状掌跖角化病家系进行对比分析。结果①点状掌跖角化病在家系中的传递符合常染色体显性遗传模式;②中国汉族人群中点状掌跖角化病的临床表型特征为点状角化丘疹不规则的分布于掌跖部;③发病年龄跨度较大,可从十几岁至五十岁左右;④大多数家系存在遗传早现现象(antic ipation);⑤同一家系中或不同家系之间患者的表现度(expressivity)可存在明显差异。结论点状掌跖角化病是一种具有高外显率的常染色体显性遗传性皮肤病,临床表型为点状角化丘疹不规则的分布于掌跖部,但不同患者表现度可存在明显差异。     

伴指间关节畸形的掌跖角化病家系基因突变检测

目的：检测一掌跖角化病家系致病基因的突变。方法：收集一具有4例患者的掌跖角化病家系和50位正常人的血液样本，抽提基因组DNA，PCR扩增致病基因（角蛋白9基因，KRT9）的外显子区，测序分析PCR产物。结果：该家系中4例患者的KRT9基因第1外显子第160位密码子发生AAT→AGT的突变，导致第160位的天门冬氨酸被丝氨酸取代（N160S），正常人中未发现此突变。结论：KRT9基因的AAT→AGT突变（N160S）是导致该家系发生弥漫性掌跖角化病的原因。     

掌跖角化病致病基因研究进展

掌跖角化病是一组以掌跖表皮角化过度为特征的遗传性皮肤病,包含多种表现亚型.近来,掌跖角化病遗传学发病机制的研究取得很大进展,已确定一些不同临床表现型掌跖角化病的致病基因,目前认为,角蛋白1、角蛋白9、角蛋白16、桥粒芯糖蛋白、桥斑蛋白、连接蛋白26、组织蛋白酶C、ARS等基因突变均能导致掌跖角化病的产生,且越来越多新的突变基因位点被发现,推动遗传性掌跖角化病致病基因的研究进程.     

表皮松解性掌跖角化病研究进展

表皮松解性掌跖角化病是一种常染色体显性遗传性单基因病,以掌跖部对称性弥漫性角化过度为主要特征,其组织学特点为表皮松解性角化过度.目前已从分子水平上阐明表皮松解性掌跖角化病由角蛋白9及角蛋白1的基因突变引起.此外,环境及药物卡培他滨也可能为其致病因素.表皮松解性掌跖角化病主要以对症治疗为主,小干扰RNA的研究逐步成为热点,为表皮松解性掌跖角化病的基因治疗提供一定的理论基础.随着对此病分子基础的研究,产前诊断的技术正不断发展.     

角化性皮肤病

中国汉族人5家系40例点状掌跖角化病临床及遗传特点分析；遗传性掌跖角化病一家系；掌跖角化症并发牙周病；阿维A治疗多发性日光性角化病1例；日光性角化病的治疗（综述）；     

长岛型掌跖角化病:一例纯合缺失的SERPINB7基因突变

目的报道1例长岛型掌跖角化病,确定其致病基因突变。方法在先证者家系调查的基础上,收集家系患者和正常人的血样,并采集正常对照血样100份,采取聚合酶链反应技术对长岛型掌跖角化病致病基因SERPINB7基因进行扩增,并对其产物进行测序。结果先证者存在SERPINB7基因7号外显子的c.650-653delCTGT(p.S217Lfs*7)纯合突变。先证者父母为杂合缺失。结论 SERPINB7基因的c.650-653delCTGT(p.S217Lfs*7)纯合突变是引起患者长岛型掌跖角化病的原因,这是该疾病、该位点作为纯和突变的首次报道。     

长岛型掌跖角化病:SERPINB7基因突变位点研究

目的报道2例长岛型掌跖角化病,确定其致病基因突变。方法收集患者及其中1例母亲外周血和临床资料,提取基因组DNA,PCR扩增SERPINB7基因8个外显子及其侧翼序列,对扩增产物进行DNA测序以查找基因突变位点。结果 2例患者均存在SERPINB7基因c.796CT杂合突变伴c.455GT杂合突变,前者可导致编码蛋白质第266位氨基酸出现终止改变(p.R266*),后者可导致第6外显子第1个核苷酸发生改变,使得该外显子的剪接受体位点消失。例1患者母亲为c.455GT杂合突变而不伴另一突变。正常对照未见这2种突变。结论 SERPINB7基因的c.796CT和c.455GT突变是引起2例患者长岛型掌跖角化病的原因。     

角化性皮肤病

20080184 P16、P21^WAH／CIP1 PCNA和cyclinE在脂溢性角化病中的表达及其意义；20080185 伴指间关节畸形的掌跖角化病家系基因突变检测；20080186 先天性角化不良研究进展（综述）；20080187 微波治疗慢性苔藓样角化病9例分析；20080188 进行性对称性红斑角化症1例。     

Hereditary skin diseases of anchoring fibrils.

Remarkable progress has been made in the last few years in understanding the functions of the anchoring fibrils, polymers of collagen VII, that connect the epidermal basement membrane with the dermal connective tissue. Novel insights into the biology of these fibrils have been gained from studies on dystrophic epidermolysis bullosa (DEB), a group of inherited blistering disorders caused by abnormalities of the anchoring fibrils. Mutations in the COL7A1 gene encoding collagen VII have been disclosed in a number of DEB families, and the mutation analyses and studies on genotype-phenotype correlations in DEB have revealed an unusual complexity of the gene defects and their biological consequences. In analogy to heritable disorders of other collagen genes, predictable phenotypes of COL7A1 mutations causing premature termination codons (PTC) or dominant negative interference have been observed. However, collagen VII seems to be unique among collagens in that many mutations lead to minimal phenotypes, or to no phenotype at all. Furthermore, the mild DEB phenotypes can be severely modulated by a second mutation in individuals compound heterozygous for two different COL7A1 defects. Therefore, not only definition of mutations with diagnostic analyses, but also cell biological, protein chemical and suprastructural studies of the mutated molecules are required for understanding the pathomechanisms underlying DEB.     

Recurrent molecular abnormalities in type VII collagen in southern Italian patients with recessive dystrophic epidermolysis bullosa

In this study we searched for mutations in the type VII collagen gene (COL7A1) in 10 families from Southern Italy with severe generalised recessive dystrophic epidermolysis bullosa using PCR amplification of genomic DNA, heteroduplex analysis and direct nucleotide sequencing. Our principal aim was to identify any recurrent mutations in COL7A1 that might facilitate future mutation detection strategies in this population. Three recurrent COL7A1 mutations were delineated in six of the 10 families: a frameshift mutation in exon 4, 497insA, was detected in three affected individuals from three families, a deletion mutation at the acceptor splice site of intron 114/exon 115, 8441-14del21, was found in five patients in three of the families, and an intron 49 acceptor splice site mutation, 4783-1 G-to-A, was identified in three subjects in two families (GenBank accession no, L02870). Haplotype analyses showed evidence for propagation of common ancestral mutant COL7A1 alleles for each of these recurrent mutations. These results contribute significantly to understanding the nature of COL7A1 pathology in patients from Southern Italy and in designing future approaches to mutation detection.     

Mutations in AAGAB underlie autosomal dominant punctate palmoplantar keratoderma

Punctate palmoplantar keratoderma type 1 (PPPK1) is a rare autosomal dominant inherited skin disease, characterized by multiple hyperkeratotic lesions on the palms and soles. The causative gene for PPPK1 has been identified as AAGAB, which encodes α‐ and γ‐adaptin‐binding protein p34. We describe the clinical features in three unrelated families with PPPK1, and report three recurrent causative mutations in AAGAB.     

Expanding the COL7A1 mutation database: novel and recurrent mutations and unusual genotype-phenotype constellations in 41 patients with dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa (DEB), a heterogeneous hereditary skin disorder characterized by trauma-induced blistering and scarring, affects thousands of families worldwide. The clinical manifestations extend from minor nail dystrophy to severe life-threatening blistering, making early molecular diagnosis and prognostication of utmost importance for the affected families. DEB is caused by mutations in the COL7A1 gene encoding collagen VII in the skin. Molecular diagnostics and genotype-phenotype correlations in DEB remain complex owing to the gene structure, large variety of mutations, high rate of novel mutations, complex protein structure and assembly, and the heterogeneity of phenotypes. Here, we report an efficient strategy for COL7A1 mutation detection using direct automated DNA sequencing and implementation of software tools. With this approach, COL7A1 mutations of 41 DEB families were disclosed. Twenty-four mutations were novel and two recurrent. Elucidation of biological consequences of the mutations helped define disease mechanisms, but also revealed several unusual genotypic and/or phenotypic constellations, which impeded the diagnostics and prognostication. In addition, the studies disclosed a de novo mutation in recessive DEB and two new polymorphisms in the COL7A1 gene.     

Dilemmas in distinguishing between dominant and recessive forms of dystrophic epidermolysis bullosa

BACKGROUND: Dystrophic epidermolysis bullosa (DEB) is a heterogeneous inherited blistering skin disorder. The mode of inheritance may be autosomal dominant or recessive but all forms of DEB result from mutations in the gene encoding the anchoring fibril protein, type VII collagen, COL7A1. Consequently, in spite of careful clinical and skin biopsy examination, it may be difficult to distinguish mild recessive cases from de novo dominant disease in families with clinically normal parents and no other affected siblings; this distinction has significant implications for the accuracy of genetic counselling. OBJECTIVES: To assess whether COL7A1 mutation analysis might help determine mode of inheritance in mild to moderate DEB. METHODS: We performed COL7A1 screening using heteroduplex analysis and direct nucleotide sequencing in four individuals with mild to moderate "sporadic" DEB and clinically unaffected parents. RESULTS: In each patient, we identified a heterozygous glycine substitution within the type VII collagen triple helix. However, in two cases these mutations had been inherited in trans with a non-sense mutation on the other allele (i.e. autosomal recessive DEB). In the other two cases, no additional mutation was identified and neither mutation was present in parental DNA (i.e. de novo dominant disease). CONCLUSIONS: This study highlights the usefulness of DNA sequencing in determining the inherited basis of some sporadic cases of DEB. However, delineation of glycine substitutions should prompt comprehensive COL7A1 gene sequencing in the affected individual, as well as clinical assessment of parents and mutation screening in parental DNA, if the true mode of inheritance is to be established correctly.     

COL7A1与PLEC双基因突变致大疱性表皮松解症一例国内首报

【摘要】 目的 对1例营养不良型大疱性表皮松解症患儿家系进行基因突变分析。方法 收集1例营养不良型大疱性表皮松解症患儿临床资料，提取患儿及其父母外周血DNA进行全基因组外显子测序，将测序结果与既往报道的大疱性表皮松解症基因进行比对，比对结果采用Sanger测序方法进行验证并预测生物学信息，在100例健康对照中验证该位点。结果 患儿存在复合杂合突变，共携带3个致病突变，即COL7A1基因c.3625_3635 del11、c.6270delT突变和PLEC基因c.12772G＞A突变。其中COL7A1基因c.6270delT突变和PLEC基因c.12772G＞A突变皆为新发突变。COL7A1基因c.3625_3635 del11及c.6270delT突变来自父亲，导致肽链合成提前终止，产生截短蛋白；PLEC基因c.12772G＞A突变来自母亲，导致网蛋白第4258位谷氨酸被赖氨酸替代（p.Glu4258Lys）。结论 该患儿是由COL7A1与PLEC双基因突变所致的常染色体隐性遗传营养不良型大疱性表皮松解症。     

Dominant dystrophic epidermolysis bullosa caused by a novel G2037R mutation and by a known G2028R mutation in the type VII collagen gene (COL7A1)

An autosomal dystrophic epidermolysis bullosa (DDEB) is a hereditary mechanobullous disease characterized by blistering of the skin and the mucous membrane. DDEB is caused by a heterozygous mutation in the COL7A1 gene encoding type VII collagen, the major component of anchoring fibrils, and phenotypically classified into several types. We experienced two boys with DDEB and examined the mutation analyses of the COL7A1 genes of the two patients and their fathers to clarify the relationship between the genotypes and phenotypes, that is, the mutation sites of COL7A1 gene and the clinical types of DDEB. The case 1 and 2 patients and their fathers revealed a heterozygous nucleotide G to A transition at position 6109 and 6082 in 73 exon of COL7A1, which resulted in a glycine to arginine substitution (G2037R and G2028R), respectively. G2037R found in the case 1 patient was a novel mutation. There was no clear relationship recognized between the two mutation sites in the COL7A1 gene and the clinical variations.     

Mutational founder effect in recessive dystrophic epidermolysis bullosa families from Southern Tunisia

Dystrophic epidermolysis bullosa (DEB) is a group of heritable bullous skin disorders caused by mutations in the COL7A1 gene. One of the most severe forms of DEB is the severe generalized [recessive dystrophic epidermolysis bullosa (RDEB-SG)] subtype, which is inherited in an autosomal recessive manner. This subtype is most often due to COL7A1 mutations resulting in a premature termination codon on both alleles. We report here, the molecular investigation of 15 patients belonging to 14 nuclear families from the city of Sfax in Southern Tunisia, with clinical features of RDEB-SG complicated by squamous cell carcinoma in 3 patients. We identified two novel mutations, p.Val769LeufsX1 and p.Ala2297SerfsX91, in addition to one previously reported mutation (p.Arg2063Trp). The p.Val769LeufsX1 mutation was shared by 11 families and haplotype analysis indicated that it is a founder mutation. The p.Ala2297SerfsX91 mutation was a private mutation found in only one family. Together with the previously described recurrent mutations in Tunisia, screening for the founder p.Val769LeufsX1 mutation should provide a rapid molecular diagnosis tool for mutation screening in RDEB patients from Southern Tunisia and possibly from other Mediterranean populations sharing the same genetic background.     

二例遗传性大疱性表皮松解症基因突变研究

目的:检测分析2例遗传性大疱性表皮松解症患者致病基因及突变位点。方法:收集患者资料,提取患者及父母外周血DNA,利用全基因组外显子测序筛查致病基因,经生物信息学分析获得致病变异;随后用Sanger测序在患者及其亲属中验证该突变。结果:患者1父母表型正常,患者2父亲有相似临床表现。患者1携带COL7A1基因73号外显子c.6082G>A(p.G2028R)的错义突变,其父母未发现该突变。患者2及其父亲携带2个致病的错义突变,即COL7A1基因c.6235G>A(p.G2079R)突变和KRT5基因c.499G>A(p.E167K)突变,其母未发现该突变。结论:散发患者存在的COL7A1基因突变属于新生突变;患者2及其父亲同时携带COL7A1基因和KRT5基因的杂合错义突变,为国内外首次报道。