遗传性大疱性表皮松解症的最新分类

遗传性大疱性表皮松解症(EB)是一组由于遗传缺陷所造成的以皮肤大疱为主要表现的疾病。自上世纪60年代以来,EB的分类经历了三次修订和更新,最新的分类方法将其分为单纯型(EBS)、交界型(JEB)、营养不良型(DEB)和Kindler综合征四个临床类型,各型又包括多种不同的亚型。     

嵌合突变在显性营养不良型大疱性表皮松解症中的研究进展

显性营养不良型大疱性表皮松解症是一种编码Ⅶ型胶原蛋白的COL7A1基因突变导致皮损的遗传性皮肤病,其临床表现为皮肤经摩擦后产生水疱、糜烂、结痂,愈后留有瘢痕及萎缩。近年发现,显性营养不良型大疱性表皮松解症患者的不发病父母可能存在生殖腺嵌合现象。随着对嵌合突变研究的日渐成熟,更深入地了解嵌合突变与显性营养不良型大疱性表皮松解症临床表型之间的相关性,认识显性营养不良型大疱性表皮松解症的发生。在对后代进行遗传风险咨询时,考虑是否存在生殖系嵌合对产前基因诊断有很大的帮助。     

Inherited epidermolysis bullosa: new diagnostic criteria and classification

Epidermolysis bullosa (EB) is a group of inherited, mechanobullous disorders caused by mutations in various structural proteins in the skin. There have been several advances in the classification of EB since it was first introduced in the late 19th century. We now recognize four major types of EB, depending on the location of the target proteins and level of the blisters: EB simplex (epidermolytic), junctional EB (lucidolytic), dystrophic EB (dermolytic), and Kindler syndrome (mixed levels of blistering). This contribution will summarize the most recent classification and discuss the molecular basis, target genes, and proteins involved. We have also included new subtypes, such as autosomal dominant junctional EB and autosomal recessive EB due to mutations in the dystonin (DST) gene, which encodes the epithelial isoform of bullouspemphigoid antigen 1. The main laboratory diagnostic techniques—immunofluorescence mapping, transmission electron microscopy, and mutation analysis—will also be discussed. Finally, the clinical characteristics of the different major EB types and subtypes will be reviewed.     

Diagnosis and clinical features of epidermolysis bullosa acquisita

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune subepidermal blistering disease characterized by immune deposits on anchoring fibrils of cutaneous and mucosal basement membrane zones. It is due to circulating antibodies directed to type VII collagen. Clinical manifestations include a classical form with skin fragility, blisters and scars on trauma-prone surfaces, an inflammatory form, and a cicatricial pemphigoid-like form. Specialized tests available in only certain laboratories are necessary to confirm a diagnosis of EBA, such as immunoelectron microscopy, immunoblotting, or ELISA using recombinant proteins. A frequent association between EBA and Crohn disease has been observed.     

The clinical spectrum of dystrophic epidermolysis bullosa

BACKGROUND: Dystrophic epidermolysis bullosa (DEB) is a genodermatosis resulting from mutations in COL7A1, the gene encoding type VII collagen. The site and specific nature of the underlying mutation determine the clinical phenotype, which ranges widely from a severe mutilating condition to a relatively mild disorder. OBJECTIVES: To document the clinical spectrum of DEB within a defined complete population. METHODS: Since 1992, when compilation of the U.K. epidermolysis bullosa register began, an exhaustive search for DEB sufferers within the Scottish population has been undertaken and their clinical features comprehensively recorded. RESULTS: One hundred and twenty-eight DEB sufferers have been identified within the Scottish population. In descending order, the frequencies of the different forms of DEB were dominant DEB (DDEB) in 88 individuals (68%), DEB of uncertain inheritance in 24 (19%) and recessive DEB (RDEB) in 16 patients (13%). Within this latter group, nine (7%) had the mutilating Hallopeau-Siemens subtype (RDEB-HS), five (4%) had localized (RDEB-loc) and two (2%) had a predominantly flexural (inverse) form of RDEB. During the study, two patients with RDEB died from squamous cell carcinomas (SCCs), one originating in the skin and the second arising in the oesophagus. Gastrointestinal problems such as dysphagia, constipation and anal fissures, and restriction of mouth opening were experienced by the majority of patients with RDEB and by a significant minority of DDEB sufferers. Pseudosyndactyly was most severe in RDEB-HS, all those over 9 years of age having mitten deformities of the hands. Milder pseudosyndactyly or flexion contractures of the fingers were present in younger patients with this subtype, in most adults suffering from other subtypes of RDEB and in 6% of those with DDEB. External ear involvement, a feature not often reported in DEB, was common in RDEB and also occurred in a minority of those with DDEB. Pruriginous lesions and albopapuloid lesions were each present in both DDEB and RDEB. CONCLUSIONS: Most patients with DEB have relatively mild dominantly inherited disease, only a minority suffering from severe recessive subtypes. Scarring, gastrointestinal involvement, albopapuloid lesions and a pruriginosa-like pattern each occur in both DDEB and RDEB. With increasing age, SCC is a major cause of morbidity and mortality.     

The clinical spectrum of epidermolysis bullosa simplex

As part of the U.K. National Epidermolysis Bullosa Register, we have systematically recorded clinical information on 130 (77%) of the 168 known Scottish epidermolysis bullosa simplex (EBS) sufferers. Three subtypes of EBS were recognized: Dowling–Meara (EBS‐DM), Weber–Cockayne (EBS‐WC) and Köbner (EBS‐Kb), seen in 5%, 42% and 53% of patients, respectively. As there is considerable overlap between EBS‐WC and EBS‐Kb, with both phenotypes frequently seen within the same pedigree, EBS‐WC is best regarded as a milder variant of EBS‐Kb rather than a separate disorder. Improvement with age is common in all variants of EBS, but is not invariable. Pain due to acral blistering in EBS‐Kb/EBS‐WC has a more marked impact on life‐style than the blisters of EBS‐DM. Oral blistering, nail involvement and aplasia cutis congenita occur in all EBS subtypes and laryngeal involvement is a feature of EBS‐DM. Seasonal variation is not seen in EBS‐DM but is common in EBS‐Kb/EBS‐WC.     

Inherited epidermolysis bullosa: clinical and therapeutic aspects

Inherited epidermolysis bullosa (EB) is a heterogeneous group of genetic disordersthat present with skin and, in some cases, mucosal fragility, predisposing patientsto the development of blisters and/or erosions after minimal trauma or friction.Children with a recurrent history of these kinds of lesions or neonates that presentthem in the absence of another reasonable explanation should be investigated.Diagnosis must be based on clinical and histopathological findings. To date,management of inherited EB basically consists in avoiding traumas that triggerlesions, as well as preventing infection and facilitating healing of the wounds withthe systematic use of bandages.     

Hereditary epidermolysis bullosa

The term epidermolysis bullosa (EB) includes a group of rare genodermatoses characterized by mutational impairment of the structural and functional integrity of intraepidermal adhesion and dermoepidermal anchorage. Clinically, these disorders are marked by increased skin fragility as well as characteristic mechanically inducible blisters on the skin and mucous membranes. Extracutaneous manifestations and their complications in other epithelialized organs render EB a multi‐system disease associated with significant morbidity and mortality. Cornerstones of a dynamically changing healthcare structure include precise and early diagnosis; coordinated, multidisciplinary, individually adjusted patient care at specialized centers; optimized symptomatic therapies; and access to research‐based, potentially curative therapeutic strategies.     

Dystrophic epidermolysis bullosa

Involvement of the large intestine in a long standing case of dystrophic epidermolysis bullosa was characterized by recurrent episodes of diarrhoea synchronizing with exacerbation ofthe skin lesions. The radiological investigations revealed two narrow segments, one each in the descending and transverse colon, with ulcer craters in the lower part of the former. The haustra from the distal half of the transverse colon to the sigmoid colon were lost.     

Inherited epidermolysis bullosa: New diagnostics and new clinical phenotypes

Inherited epidermolysis bullosa (EB) is a group of heterogeneous genetic disorders characterized by skin fragility. EB comprises a large spectrum of phenotypes, ranging from severe cutaneous and extracutaneous involvement caused by lack of key adhesion proteins, to mild cutaneous fragility caused by subtle molecular defects. Disease‐causing variants in 20 different genes account for the genetic and allelic heterogeneity of EB. Here, we discuss the development of laboratory methods that enabled these discoveries and the clinical and molecular features of some new EB entities elucidated during the past 5‐6 years.     

Progress in epidermolysis bullosa: from eponyms to molecular genetic classification

Epidermolysis bullosa, a clinically and genetically diverse group of heritable mechanobullous disorders characterized by skin fragility in the cutaneous basement membrane zone, has become a prototype for the recent progress in molecular genetics of genodermatoses. The different forms of epidermolysis bullosa have been linked to mutations in no less than 10 distinct genes encoding the major structural basement membrane zone proteins. This information has formed a basis for refined molecular classification with prognostic implications, improved genetic counseling, and prenatal and preimplantation genetic diagnosis.