泛发性萎缩性良性大疱性表皮松解症我国首例报道

目的 报道我国首例泛发性萎缩性良性大疱性表皮松解症家系。方法 对该家系先证者的临床资料、组织病理、透射电镜、间接免疫荧光检查进行分析。结果 该患者除了先天性大疱性表皮松解症的症状外,特征性表现是萎缩性秃发和牙齿发育不良。透射电镜检查裂隙位于基底膜透明板,同时伴半桥粒数目减少和发育不良。间接免疫荧光检查发现患者针对大疱性类天疱疮抗原2的荧光消失,说明本例发病与编码大疱性类天疱疮抗原2的基因COL17A1的缺陷有关。结论 此例为泛发性萎缩性良性大疱性表皮松解症,是交界性大疱性表皮松解症的一种特殊亚型。泛发性萎缩性良性大疱性表皮松解症有一定的临床特点,透射电镜和间接免疫荧光检查对于正确诊断和分型十分重要,并对进一步基因突变位点研究有指导作用。     

Non-Herlitz junctional epidermolysis bullosa without hair involvement associated with BP180 deficiency

Junctional epidermolysis bullosa (JEB) is a clinically and genetically heterogeneous recessively inherited blistering disease of the skin and mucous membranes due to impaired epithelial adhesion. In particular, defective expression of the 180-kD bullous pemphigoid antigen (BP180) has been correlated to a non-lethal (non-Herlitz) form of JEB, generalized atrophic benign epidermolysis bullosa (GABEB), characterized by widespread skin blistering healing with atrophy and by atrophic alopecia with onset in childhood. We report the case of a 33-year-old man suffering from a generalized blistering skin disorder since birth. He also presented nail dystrophy and tooth abnormalities. Mucosal involvement was limited to gingival erosion. Alopecia was absent and body, axillary and pubic hair were normal. Immunofluorescence analysis showed a markedly reduced expression of BP180, electron microscopy studies evidenced hypoplastic hemidesmosomes and Northern blot analysis confirmed a striking decrease in the amount of BP180 mRNA. The clinical features of our patient confirm that BP180 deficiency usually results in a non-Herlitz JEB form. However, the degree of skin, mucous membranes and hair involvement appears more variable and less typical than originally described for GABEB.     

先天性大疱性表皮松解症基底膜带分子的研究

目的：通过透射电镜和免疫荧光研究先天性大疱性表皮松解症患者的基底膜带分子。方法：分析7个组织病理表现为表皮下疱的先天性大疱性表皮松解症患者的透射电镜和免疫荧光表现。结果：电镜检查1例为基底膜透明板裂隙,即JEB,其余6例为基底膜下裂隙,即DEB,间接免疫荧光检查此例JEB是BPAG2缺陷。结合临床资料诊断为泛发型萎缩性良性大疱性表皮松解症（generalized atrophic benign EB,GABEB),这是我国首例报告;6例DEB患者透射电镜和免疫荧光检查辅助诊断DDEB和RDEB。结论：先天性大疱性表皮松解症是一组疾病,电镜和免疫荧光检查对于分型和明确诊断是必需的,间接免疫荧光检查还可以指导进一步的基因诊断。     

Diminished expression of the extracellular domain of bullous pemphigoid antigen 2 (BPAG2) in the epidermal basement membrane of patients with generalized atrophic benign epidermolysis bullosa

Abstract Generalized atrophic benign epidermolysis bullosa (GABEB) is a nonlethal form of junctional epidermolysis bullosa characterized by generalized skin and mucosal blisters that heal with atrophy; other features include alopecia, nail dystrophy, large melanocytic nevi, and autosomal recessive inheritance. The specific aim of this study was to identify an abnormality in epidermal basement membrane adhesion molecules in well characterized GABEB patients that would explain why these subjects' epidermis separates from their epidermal basement membrane. Cryostat sections of nonlesional skin from 8 GABEB patients in 5 different families as well as skin from normal volunteers (controls) were studied by indirect iminunofluorescence microscopy using rabbit antiserum directed against a BPAG1 fusion protein or monoclonal antibodies directed against the extracellular domain of BPAG2 (HD18 and 233), epiligrin (P1E1), laminin 5 (GB3), types IV and VII collagen, or integrin subunits α2, α3, β, α6, or β4. In these studies, monoclonal antibodies HD18 and 233 showed no reactivity and diminished reactivity, respectively, to the epidermal BM of all GABEB patients. Interestingly, in one patient, the absent or diminished reactivities of monoclonal anti-BPAG2 antibodies were limited to well demarcated portions of an otherwise intact epidermal basement membrane. Moreover, BPAG1, epiligrin, laminin 5, types IV and VII collagen, and all integrin subunits under study were expressed in the same manner in both GABEB and normal human skin. These findings identify an abnormality in the extracellular domain of BPAG2 in the skin of GABEB patients. BPAG2 (type XVII collagen) is a transmembrane, hemidesmo-some-associated molecule whose extracellular domain resides at the exact level where blisters develop in the skin of patients with GABEB. Impairment of this adhesion molecule may play a key role in the pathogenesis of this inherited subepidermal bullous disease.     

180-kDa bullous pemphigoid antigen defective generalized atrophic benign epidermolysis bullosa: report of four cases with an unusually mild phenotype

Generalized atrophic benign epidermolysis bullosa (GABEB) is a rare variant of non-lethal junctional epidermolysis bullosa characterized by generalized skin blistering healing with atrophy and by atrophic alopecia with onset in childhood. Other features include mild mucosal blistering, dental abnormalities and nail dystrophy. We report four additional cases of GABEB from two families originating from the same isolated village. The patients shared an unusually mild clinical phenotype with cutaneous blisters strictly limited to trauma sites and rare occurrence of oral mucosal lesions. Scalp, eyelash and eyebrow alopecia was present in only two cases. Immunofluorescence studies showed a markedly reduced expression of the 180-kDa bullous pemphigoid antigen (BP180), and northern analysis of cultured keratinocytes indicated that the gene encoding for BP180 is affected in these GABEB patients.     

Neonatal Junctional Epidermolysis Bullosa: Treatment Conundrums and Ethical Decision Making

Junctional epidermolysis bullosa (JEB), generalized severe (previously called JEB, Herlitz-type) has an extremely poor prognosis, with a mean age of death at 5 months old and most dead before age 3 years. We describe a typical case of a neonate with JEB who developed failure to thrive before his death from fungal septicemia at 4 months of age. This case highlights the ethical considerations of invasive treatments such as gastrostomy tube placements, intubations, and central line placements in neonates with JEB. We review the literature as well as discuss the ethical conundrums in the care of patients with JEB and other severe forms of epidermolysis bullosa.     

Generalized atrophic benign epidermolysis bullosa

Generalized atrophic benign epidermolysis bullosa (GABEB) is a rare autosomal recessive variant of junctional epidermolysis bullosa. A typical feature in these patients is the cicatricial alopecia resembling male pattern baldness; in this paper we describe a case of GABEB with particular attention to this characteristic.     

Large melanocytic nevi in generalized atrophic benign epidermolysis bullosa (epidermolysis bullosa nevi)

Generalized atrophic benign epidermolysis bullosa (GABEB) is a nonlethal form of junctional epidermolysis bullosa. The expression of type XVII collagen (180 kDa bullous pemphigoid antigen) or of laminin 5 is markedly reduced in the skin. A 13-year-old patient with GABEB, developed several large, asymmetric, irregularly pigmented melanocytic nevi with poorly defined borders. They had appeared following blister formation since 8 years of age. Histological examination revealed an irregular proliferation of monomorphous melanocytes at the dermoepidermal junction. Small nests of melanocytes were focally present. This case further emphasizes the difficulty in differentiating nevi appearing in GABEB from malignant melanoma.     

Generalized atrophic benign epidermolysis bullosa--poor prognosis associated with chronic renal failure

Generalized atrophic benign epidermolysis bullosa (GABEB) is an autosomal recessive form of junctional epidermolysis bullosa, with milder clinical features than the Herlitz subtype. A 25-year-old man presented with the clinical and histological findings of GABEB. At the initial visit, laboratory tests revealed that he also had chronic renal failure (CRF). Usually, GABEB has a good prognosis. However, in this case, the patient had CRF as an associated complication. He died of an intracranial haemorrhage combined with sepsis after 3 weeks of hospitalization. This case suggests that renal complications can occur in this relatively mild form of epidermolysis bullosa, and may contribute to morbidity and premature mortality.     

Abnormal expression of hemidesmosome-like structures by junctional epidermolysis bullosa keratinocytes in vitro

Hemidesmosomes are frequently rudimentary in junctional epidermolysis bullosa (JEB), and JEB keratinocytes display abnormal attachment to the substrate in culture. Our aim was to determine whether this abnormality reflects defective hemidesmosome synthesis in vitro. Keratinocytes from five JEB patients were cultured under standard conditions. Control cultures, from four healthy males, three patients with dystrophic EB (DEB), and one patient with the simplex variant (EBS), were also examined. Post-confluent cultures were processed for transmission electron microscopy. Hemidesmosome-like structures were counted in electron micrograph montages. The number of hemidesmosome-like structures in JEB cultures (0.97 +/- 0.57, per 10 microns of basal cell membrane) was approximately 17% of the value for normal controls (5.81 +/- 3.08, P less than 0.02). The values for EBS (3.72) and DEB (3.28 +/- 1.44) were not statistically different from normal controls. In addition hemidesmosome-like structures in JEB cultures were morphologically ill-defined, compared with those from controls. This correlated with the loose apposition between JEB keratinocytes and the substrate, which appeared tight in controls. JEB keratinocytes continue to express in vitro a major phenotypic abnormality which characterizes the disease in vivo. Therefore, this model should prove useful in studies determining the pathogenesis and possible new treatments of JEB.     

Laminin-5 mutational analysis in an Italian cohort of patients with junctional epidermolysis bullosa

Junctional epidermolysis bullosa (JEB) is a rare genodermatosis characterized by dermal-epidermal separation that is caused by mutations in the genes encoding hemidesmosomal components and laminin-5, the major epithelial adhesion ligand. Here, we report on the mutational analysis of LAMA3, LAMB3, and LAMC2 genes encoding laminin-5 chains in 19 Italian patients, 11 affected with the severe Herlitz (H JEB) and eight with the mild non-Herlitz variant of JEB (non-H JEB). Eighteen mutations, seven of which were novel, were identified and their consequences analyzed at the mRNA and protein level. Premature termination codon mutations in both alleles of LAMB3 or LAMC2 genes were found in nine of the 11 H JEB patients, with a prevalence of mutations in LAMC2. In one case, a homozygous frameshift mutation in LAMB3 was associated to illegitimate splicing leading to non-H JEB. One H JEB patient showed a large intragenic duplication within LAMC2, a genetic defect so far uncovered in laminin-5 genes. Splicing or missense mutations, were prevalent in non-H JEB patients. Collectively, five mutations appeared to be frequent in laminin-5 JEB patients: R635X, 29insC, E210K, W143X in LAMB3 and R95X in LAMC2. These recurrent mutations account for approximately 44% of laminin-5 JEB alleles in Italian patients.     

Junctional epidermolysis bullosa keratinocytes in culture display adhesive, structural, and functional abnormalities.

An unusual, elongated, refractile cell morphology was observed in keratinocytes cultured from three patients with non-lethalis forms of junctional epidermolysis bullosa (JEB). To determine whether these changes might be related to altered cell adhesion, keratinocyte strains established from one patient were examined for adhesive, structural, and functional characteristics. JEB keratinocytes expressed keratin tonofilaments, as determined by staining with AE1 monoclonal antibodies and direct observation of tonofilaments by electron microscopy. JEB keratinocytes showed diminished cell-substratum adhesions, judged by interference reflection microscopy. Areas of diminished cell-substratum adhesion corresponded to F-actin-rich cell adhesions (focal adhesions) and not to cellular areas that abundantly express hemidesmosomal antigens. Analysis of cell-substratum adhesion by electron microscopy revealed extensive areas of cell-substratum separation in JEB keratinocytes that were not present in normal keratinocytes maintained in serum-free medium. Normal keratinocytes displayed numerous regions of focal contact between the ventral plasma membrane and the culture substratum, but these structures were not seen in JEB keratinocytes. Bundled actin filaments (stress fibers) were greatly diminished in expected regions of cell-substratum adhesion in JEB keratinocytes and, instead, displayed disorganized individual filaments. The growth rate of JEB keratinocytes was quite slow in culture, with a population doubling time of 2.7 d versus 1.5 d for normal keratinocytes under identical conditions. JEB keratinocytes also displayed a reduced ability to aggregate into colonies upon exposure to medium with increased extracellular calcium. JEB keratinocytes thus display adhesive, structural, and functional abnormalities that suggest this cell type may be central to the pathogenesis of junctional epidermolysis bullosa. Study of affected keratinocytes could be important to characterize associated molecular pathologies.     

Mosaic expression of uncein and 180-kDa bullous pemphigoid antigen in generalized atrophic benign epidermolysis bullosa

Immunofluorescence microscopy of epidermodermal junction components in serial cryosections from the perilesional skin of a patient with generalized atrophic benign epidermolysis bullosa (GABEB) showed broken line-like staining of both BPAG2 (180-kDa bullous pemphigoid antigen) and uncein (antigen of 19-DEJ-l monoclonal antibody), whereas integrin α6 and laminin 5 were continuously expressed along the basement membrane zone. Immunoelectron microscopy revealed a mosaic distribution of the BPAG2/uncein positive and negative cells. BPAG2, a candidate protein of GABEB, probably has a close connection with uncein, an anchoring filament component.     

Hemidesmosome heterogeneity in junctional epidermolysis bullosa revealed by morphometric analysis

In order to examine the claim for a numerical and structural abnormality of the hemidesmosomes in junctional epidermolysis bullosa (JEB), a morphometric analysis of unseparated dermal-epidermal junction was undertaken in 11 subjects with JEB. Of these, 5 died in infancy with "lethal" disease, 3 were children still alive at 1-6 years with "indeterminate" disease, and 3 were females aged 20-60 years with variable phenotypic expression of "nonlethal" JEB. All the lethal cases had reduced numbers of hemidesmosomes which were small and lacked normal subbasal dense plates, with the exception of 1 patient whose hemidesmosomes were structurally and numerically normal. The principal hemidesmosome abnormality in the 3 cases with indeterminate JEB was the absence of normal subbasal dense plates. In 2 of the 3 cases of nonlethal JEB, the hemidesmosomes appeared normal, whereas in the third patient they showed a similar abnormality to that present in the majority of the lethal group. These results demonstrate that JEB is an ultrastructurally heterogeneous condition, and suggest that, even though the hemidesmosome abnormalities may be of diagnostic value, they do not correlate sufficiently well with the clinical outcome to be useful as a prognostic indicator.     

Novel compound heterozygous mutation in LAMC2 genes (c.79G>A and 382insT) in Herlitz junctional epidermolysis bullosa

Junctional epidermolysis bullosa (JEB) is a heritable blistering skin disease characterized by separation within the lamina lucida. It is caused by mutations in the LAMA3, LAMB3 and LAMC2 genes encoding the α3‐, β3‐ and γ2‐chains, respectively, of laminin‐332. JEB Herlitz type (JEB‐H) is a lethal blistering disease with severe cutaneous and extracutaneous involvements caused by null mutations in the gene encoding laminin‐332. Here, we report a proband with JEB‐H who is a compound heterozygote for two novel mutations in LAMC2; a missense mutation (c.79G>A) and an insertion mutation (382insT) leading to a premature termination codon.     

Compound heterozygosity for novel splice site mutations in the BPAG2/COL17A1 gene underlies generalized atrophic benign epidermolysis bullosa

Generalized atrophic benign epidermolysis bullosa, GABEB (OMIM# 226650), is a nonlethal variant of epidermolysis bullosa with autosomal recessive inheritance pattern. The pathogenesis of this disorder can be caused by mutations affecting two different gene/protein systems. Most of the mutations have been identified in the BPAG2/COL17A1 gene encoding a hemidesmosomal transmembrane protein, the 180 kDa bullous pemphigoid antigen (BP180), also known as type XVII collagen. The minority of the mutations are localized in the LAMB3 gene encoding the beta3 polypeptide of laminin 5. In In this study we describe a GABEB patient who showed absent expression of BP180 in the cultured keratinocytes as well as in the skin. The patient was a compound heterozygote for two different splice site mutations, 3053-1G-->C and 3871+1G-->C, affecting the extra-cellular domain of the protein. These mutations resulted in multiple aberrant splice variants, three of them causing premature termination codons for translation. This case, dealing with out-of-frame splice site mutations in BPAG2/COL17A1, attests to the molecular heterogeneity of GABEB.     

Non-lethal junctional epidermolysis bullosa in a dog

We report a 4-year-old female mongrel dog with a history since birth of erosions and atrophic skin, with pigmentation and alopecia on the face, trunk and extremities, together with dystrophic nails. Light microscopy revealed subepidermal blisters with minimal inflammation and electron microscopy confirmed that the ultrastructural site of separation site was at the lamina lucida. Indirect immunofluorescence of the dog's skin detected the positive expression of laminin 5. BPAG2, integrinα6 and type VII collagen. These clinical, ultrastructural and immunohistochemical features suggested that the dog had a non-lethal subtype of junctional epidermolysis bullosa (JEB). This is the first confirmed case of non-lethal JEB in a dog and presents a possible candidate for an animal model of gene therapy. Further study should provide important information of the phenotype, pathophysiology and prognosis of non-lethal JEB in humans.