Epidermolysis bullosa. Application of epidemiologic principles to the study of a group of rare diseases via a disease registry

The study of rare diseases may provide unique insights into new mechanisms of disease. Such research is difficult to perform, however, owing to a variety of problems associated with patient recruitment and classification, and the biases that are frequently associated with the study of rare diseases. Despite its many limitations, establishment of disease registries may facilitate this research, as evidenced by the depth and breadth of findings recently obtained in inherited epidermolysis bullosa via such a mechanism.

Defective in vivo expression and apparently normal in vitro expression of a newly identified 105-kDa lower lamina lucida protein in dystrophic epidermolysis bullosa

We have previously identified a novel 105-kDa lower lamina lucida protein detected by the autoantibodies from a group of patients who developed a unique immune-mediated subepidermal bullous dermatosis. We sought to determine if this novel basement membrane zone (BMZ) protein is normally expressed in the skin of patients with various subsets of epidermolysis bullosa (EB). Indirect immunofluorescence microscopy performed on non-lesional skin sections from patients with three major EB subsets revealed absence or significantly reduced expression of this novel BMZ protein in 20 out of 23 skin sections from patients with generalized dominant and recessive dystrophic EB. However, immunoblot analyses with the autoantibodies on Western-blotted proteins revealed that a comigrating 105-kDa protein is present in both cytosol extracts (n = 6) and conditioned media (n = 3) of cultured dermal fibroblasts derived from patients with dystrophic EB, as well as those cultured from two healthy individuals. Although the reason for such disparate findings is not known, the defective in vivo expression of this novel 105-kDa protein in dystrophic EB is presumably not due to a failure of fibroblasts to synthesize or secrete the protein. It is possible, however, that the 105-kDa protein may be unable to incorporate into the BMZ because it is produced in a dysfunctional form, or its BMZ binding site is missing. It is also possible that other structural alterations in skin BMZ, which occur in dystrophic EB, result in masking of the antigenic binding by the autoantibody when intact BMZ is probed.(ABSTRACT TRUNCATED AT 250 WORDS)

International symposium on epidermolysis bullosa. The William and Ida Friday Continuing Education Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, April 25-26, 1994. Abstracts

An international symposium on inherited epidermolysis bullosa was held at the University of North Carolina at Chapel Hill on April 25-26, 1994. All areas currently of clinical and research interest pertinent to this disease were discussed, ranging from basic epidemiologic issues to the definition of molecular defects in each of the three major types of epidermolysis bullosa and the potential for gene therapy. A major focus of this meeting was the presentation of data collected by the National Epidermolysis Bullosa Registry.

Dental caries risk in hereditary epidermolysis bullosa

Epidermolysis bullosa (EB) is a clinically diverse group of conditions characterized by skin fragility and, in certain types, marked dental involvement. The purpose of this study was to determine the prevalence of dental caries in EB and control populations. Healthy individuals and participants from the Southern Clinical Center of the National EB Registry were examined with artificial light and a #23 dental explorer. Caries levels were evaluated by chi-square analysis, regression analyses, and ANOVA (P < 0.05 being significant). The study included 252 individuals with EB, aged 2.3-71 years, and 57 similarly aged controls. The prevalence of dental caries, scored as DMFS (decayed, missing, filled surfaces), was significantly higher in the junctional (mean = 58.6) and recessive dystrophic (mean = 37.6) EB types than controls (mean = 23.2). The simplex (mean = 25.6) and dominant dystrophic (mean = 21.6) EB groups had DMFS levels similar to the control group. Individuals with recessive dystrophic EB had the most severe oral blistering and scarring and did not have generalized enamel hypoplasia. In contrast, junctional EB always was associated with generalized enamel hypoplasia yet the intraoral blistering rarely involved scarring. This study shows that dental caries is increased in dystrophic and junctional EB compared with unaffected individuals or other EB types. While rampant caries appears related to the soft tissue and enamel involvement in these two EB types, other as yet unclear cofactors also must be involved.

Prenatal exclusion of pyloric atresia-junctional epidermolysis bullosa syndrome

BACKGROUND

The pyloric atresia--junctional epidermolysis bullosa (PA-JEB) syndrome is an autosomal recessive disorder with a poor prognosis. Electron microscopy of fetal skin has been the only reliable method for prenatal diagnosis.

OBJECTIVE

The purpose of this study was to make the prenatal diagnosis of PA-JEB syndrome with a more reliable method by means of immunocytochemical probes.

METHODS

Expression of a range of basement membrane antigens was examined in different types of JEB. On the basis of the results, a fetal skin biopsy specimen was obtained for prenatal diagnosis.

RESULTS

In PA-JEB syndrome (n = 2), GB3 antigen (BM600) was normally expressed; the 19-DEJ-1 antigen was completely absent. In fetal skin at risk for PA-JEB syndrome, the 19-DEJ-1 antigen was normally expressed, and no ultrastructural abnormality was found by electron microscopy. A normal male infant was delivered at 38 weeks of pregnancy.

CONCLUSION

19-DEJ-1 monoclonal antibody serves as a useful probe for the prenatal diagnosis of PA-JEB syndrome.

The National Epidermolysis Bullosa Registry

Since its inception in 1986, the NEBR has proved to be an excellent example of how a relatively small allocation of federal research funds for the development of a registry of cases of a single rare disease can have a major impact on the rapid expansion in the depth of knowledge of not only the disease itself but of a number of associated biologic principles, including keratinization and epithelial cell-extracellular matrix interactions. At present, the NEBR is generating extensive clinical, laboratory, and demographic data, both from cross-sectional and longitudinal perspectives, as well as establishing a centralized cell and tissue bank that will serve the scientific community at large as a valuable resource for future basic research on this oftentimes devastating genetic disease.

Hereditary epidermolysis bullosa

Epidermolysis bullosa (EB) is a diverse group of disorders having blister formation as their common feature. Tissue separation occurs at variable depths in the skin and/or mucosa depending on the specific EB type. Marked oral involvement of the soft and hard tissues can produce potentially devastating alterations, with oral tissue fragility and blistering common to all EB types. Oral debilitation resulting from soft tissue scarring is limited primarily to the recessive dystrophic EB subtypes. Individuals with generalized recessive dystrophic EB typically have microstomia, obliteration of the oral vestibule, and ankyloglossia. Generalized enamel hypoplasia appears to be limited to junctional EB, whereas rampant dental caries afflicts many individuals having either junctional or generalized recessive dystrophic EB. Although systemic treatment remains primarily palliative, it is possible to prevent destruction and subsequent loss of the dentition through appropriate interventions and dental therapy. The severely affected soft and/or hard tissues frequently seen in patients having generalized recessive dystrophic and junctional EB often require aggressive dental intervention to maintain optimal oral health. Even the most severely affected individuals with EB can retain their dentition through the use of modern dental restorative techniques delivered using general anesthesia.

Immunoelectron microscopy of skin basement membrane zone antigens: a pre-embedding method using 1-nm immunogold with silver enhancement

There is no single immunoelectron microscopical method for invariably effective localization of both intracellular and extracellular antigens. We describe a simple and practicable immunogold technique that can be used to localize various skin basement membrane zone antigens at the ultrastructural level. Small pieces of skin were incubated with primary antibodies recognizing epitopes on a range of basement membrane zone-related antigens (two different lamina lucida-associated antigens, laminin, type VII collagen, fibrillin and keratin 14). This was followed by incubation with 1-nm colloidal gold-conjugated secondary antibody and subsequent silver intensification. The specimens were then processed for transmission electron microscopy. Precise immunolocalization with good ultrastructural preservation was achieved for all basement membrane zone antibodies tested. The results of basal cell keratin immunostaining showed that this microscopic approach could also be applied to some extent in the characterization of intracellular antigens. This immunoelectron microscopy technique provides a useful approach to the study of macromolecules at the basement membrane zone.

Laboratory tests for epidermolysis bullosa

Determination of the correct diagnosis and subclassification of inherited and acquired forms of epidermolysis bullosa (EB) can be exceedingly challenging because the clinical morphologic findings and routine histology are frequently nonspecific. The most precise means of diagnosing inherited EB involves the assessment of a combination of ultrastructural and antigenic features by transmission electron microscopy, immunofluorescence antigenic mapping, and EB-related monoclonal antibody studies. Acquired EB can usually be diagnosed by split skin indirect or direct immunofluorescence. When necessary, immunoelectron microscopy, immunoprecipitation, and immunoblot can be used.

Ultrastructural and immunohistochemical characterization of basal cells in three-dimensional culture models of the skin

Keratinocytes were cultured on fibroblast-free dermal substitutes made of type I collagen film (collagen dermal substitute) and an extracellular matrix gel film (matrix dermal substitute), each of which was laid on a lyophilized type I collagen sponge. The morphology of the basal keratinocytes in these three-dimensional culture models of the skin was studied ultrastructurally and immunohistochemically to assess their differentiation to basal cells. The basal keratinocytes in the artificial epidermis cultured on the collagen dermal substitute showed poorly organized tonofibril networks and desmosomes. Neither the tonofibril-hemidesmosome complex nor the lamina densa were detected along the interface, where many cytoplasmic projections of basal keratinocytes were noted. There were no detectable antigens of type IV or VII collagen, LDA-1, or laminin in the interface. Bullous pemphigoid (BP) and 1-2B7B antigens and integrins were expressed along the cytoplasmic membrane and the projections of the basal keratinocytes. A high molecular weight keratin (keratin 1, 68 kDa, 34 beta B4) was detected only in part of the uppermost layers of this artificial epidermis. In contrast, basal keratinocytes in the artificial epidermis on the matrix dermal substitute developed tonofibril networks radiating to desmosomes and hemidesmosomes, under which a primitive lamina densa was present. Basement membrane zone antigens, such as type IV and VII collagens, LDA-1 and laminin were noted along the interface as were 1-2B7B and BP antigens and integrins. Laminin and type VII collagen were also detected along or in the membrane of the endoplasmic reticulum of basal keratinocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral involvement of recessive dystrophic epidermolysis bullosa inversa

The inversa subtype of autosomal recessive dystrophic epidermolysis bullosa (EBDR-I) is a rare variant characterized by lesions involving primarily the flexural areas of the body. The purpose of this investigation was to characterize the oral manifestations of this unusual dermatologic condition. Ten individuals having EBDR-I were evaluated and compared with an age and sex-matched population of unaffected individuals that served as controls. The diagnosis of EBDR-I was confirmed by skin biopsy that demonstrated tissue separation below the lamina densa and the clinical presentation of blister formation that typically localized to flexural areas. There was clinical variability in the severity and distribution of skin involvement; however, none of the affected individuals demonstrated pronounced digital webbing, severe generalized blistering or growth retardation characteristic of the Hallopeau-Siemens form of EBDR. Oral involvement was seen in all cases with ankyloglossia, loss of tongue papillae and obliteration of the oral vestibule between the lips and gingiva being typical. The oral opening was significantly reduced in older EBDR-I individuals compared with matched controls, confirming that acquired microstomia is a characteristic of EBDR-I. The teeth were not clinically abnormal or malformed and showed no evidence of generalized enamel hypoplasia. Despite this, the prevalence of dental caries in EBDR-I individuals was significantly higher than the control group. The inversa form of EBDR presents with oral findings that are similar but generally milder than those seen in the Hallopeau-Siemens variant of EBDR.

Development defects of enamel in humans with hereditary epidermolysis bullosa

Developmental defects of enamel are often reported as a feature of the more severe forms of epidermolysis bullosa (EB). The purpose of this investigation was to determine the prevalence and character of enamel defects in each of the major hereditary EB types. Clinical evaluations were made on 237 individuals representing all of the major EB types and 58 unaffected individuals. All EB cases were categorized by phenotype, mode of inheritance and skin biopsy. The frequency of individuals having developmental enamel defects ranged from 8.6% in recessive dystrophic EB to 100% in junctional EB; 27.5% of the control population had these defects. Generalized hypoplasia characterized by either severe pitting and/or thin enamel was seen in all junctional EB cases but not in any other EB type. There was a tendency for the severe Herlitz form of junctional EB to have thin enamel while non-Herlitz junctional EB cases had less severe pitting and generally no reduction in enamel thickness. The prevalence of individuals with hypoplastic enamel bands was greater in the EB population (9.7%) than controls (1.9%). Thus individuals with simplex and dominant dystrophic EB typically have enamel defects that are similar in frequency and distribution to those of unaffected individuals. Developmental defects of enamel are a consistent feature of junctional EB, although the clinical expression is highly variable.

Identification and partial characterization of a novel 105-kDalton lower lamina lucida autoantigen associated with a novel immune-mediated subepidermal blistering disease

Certain skin basement membrane components, such as bullous pemphigoid antigens and epidermolysis bullosa acquisita antigen, were discovered as a result of an autoimmune reaction. In this report, we describe a unique lamina lucida determinant associated with a novel immune-mediated subepidermal bullous dermatosis. This unique bullous dermatosis resembled severe toxic epidermal necrolysis clinically. The histologic findings resemble dermatitis herpetiformis. Direct immunofluorescence microscopy detected linear immunoglobulin G (IgG) and C3 deposition at the cutaneous basement membrane zone of lesional and perilesional skin. Direct and indirect immunoelectron microscopy localized the IgG deposits to the lowest portion of the lamina lucida. The patient's autoantibodies, belonging to the IgG1 subclass, labeled basement membrane zone of normal intact human skin, oral mucosa, and conjunctiva, and localized to the dermal side of salt-split normal adult and neonatal human skin, but failed to react with human fetal skin up to 142 gestational days. The patient's autoantibodies failed to react with bullous pemphigoid antigens or epidermolysis bullosa acquisita antigen (type VII collagen) by immunoblotting. Instead, the patient's autoantibodies unequivocally labeled a 105-kilodalton (kD) protein in cellular extracts and conditioned media of human cultured keratinocytes and dermal fibroblasts. The titer of the patient's antibody against the cutaneous basement membrane zone and the intensity of the antibody reactivity against the 105-kD protein paralleled the patient's disease activity. Thus, this 105-kD lower lamina lucida protein represents a novel autoantigen and this patient's disease represents a novel autoantigen and this patient's disease represents a deep lamina lucida pemphigoid, distinguishable from all other known autoimmune bullous dermatoses.

Intracytoplasmic retention of type VII collagen and dominant dystrophic epidermolysis bullosa: reversal of defect following cessation of or marked improvement in disease activity

It has been recently shown that the presence of perinuclear "stellate bodies" within the epidermis in patients with a form of dominant dystrophic epidermolysis bullosa named "transient bullous dermolysis of the newborn" corresponds to collections of type VII collagen. To determine the temporal relationship of this unique immunohistochemical defect with course of clinical disease activity, we have longitudinally studied the expression of two epitopes of type VII collagen (LH 7:2; L3d) in nine patients in four such kindreds by immunofluorescence and immunoelectron microscopic technique. In every infant so studied at the time of active blistering, type VII collagen was detectable primarily within basilar and, to a lesser extent, suprabasilar keratinocytes. In contrast, type VII collagen was detectable solely in linear array along the dermoepidermal junction in skin from each patient following complete cessation or at least marked diminution of visible clinical disease activity. These findings support the hypothesis that the temporary mechanical fragility and blistering of the skin in infants with this rare subset of dominant dystrophic epidermolysis bullosa reflect the presence of reduced amounts of type VII collagen along the dermoepidermal junction, and that this diminution may be the result of either a delay in transport and integration of type VII collagen from basilar keratinocytes into the skin basement membrane or excessive phagocytosis of type VII collagen.

The genetic basis of Weber-Cockayne epidermolysis bullosa simplex

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominant skin diseases characterized by blistering, due to mechanical-stress-induced degeneration of basal epidermal cells. Recently, it was discovered that the more severe types, Dowling-Meara and Koebner, are genetic disorders of the basal epidermal keratins, keratin 5 (K5) and keratin 14 (K14). Here, we show that the mildest type of EBS, Weber-Cockayne, is also a disorder of these keratins. Affected members of two unrelated families with Weber-Cockayne EBS had a T-->G point mutation in the second base position of codon 161 of one of two K5 alleles, leading to an Ile-->Ser mutation. This mutation was not present in unaffected members or in 156 alleles from normal individuals. Linkage analyses mapped the defect to the type II keratin gene cluster on chromosome 12q11-q13 (peak logarithm of odds score at theta = 0 of 3.0), providing strong additional evidence that this mutation is responsible for the Weber-Cockayne EBS phenotype. Conserved among type II keratins, Ile-161 is in the nonhelical head domain of K5, a region previously shown to be important for 10-nm filament assembly. The mutation generates a potential substrate site for protein kinase C, which could influence intermediate filament architecture, perhaps leading to the intrafilament association seen ultrastructurally in patients with the mutation.

Hereditary epidermolysis bullosa: oral manifestations and dental management

Epidermolysis bullosa (EB) is a diverse group of disorders that have as a common feature blister formation with tissue separation occurring at variable depths in the skin and/or mucosa depending on the specific EB type. There may be marked oral involvement, potentially creating devastating alterations in the soft and hard tissues. Oral tissue fragility and blistering is common to all EB types. However, oral debilitation as a result of soft tissue scarring is primarily limited to the recessive dystrophic EB subtypes. Generalized enamel hypoplasia appears to be limited to junctional EB, although rampant dental caries is associated with many individuals having generalized recessive dystrophic EB. While systemic treatment remains primarily palliative, it is possible to prevent destruction and subsequent loss of the dentition through appropriate interventions and dental therapy. The majority of individuals with mild EB subtypes may receive dental treatment with only minor modifications in approach. Even the most severely affected individuals with EB can retain their dentition using general anesthesia and conventional restorative techniques. With aggressive preventive interventions and management of developing malocclusions using serial extraction, it also is possible to reduce the likelihood of rampant caries, achieve an acceptable occlusion without the need for active tooth movement or appliance therapy, and allow these individuals to benefit from maintaining a natural healthy dentition.

Normal molecular weight of type VII collagen produced by recessive dystrophic epidermolysis bullosa keratinocytes

Studies of the recessive dystrophic form of epidermolysis bullosa (RDEB) have suggested that an abnormality in type VII collagen may be involved in the pathogenesis of this disorder. Indirect immunofluorescence studies have shown that the staining for type VII collagen along the dermal-epidermal junction is markedly reduced or absent in all but rare cases of severe, generalized RDEB. These findings imply that the genetic defect may involve type VII collagen but do not exclude the possibility that the alterations demonstrated are secondary, for example, to nonspecific proteolysis of type VII collagen. To evaluate the ability of cells of affected patients to produce type VII collagen, we cultured keratinocytes from a severely affected patient and immunoprecipitated type VII collagen from the cells. Keratinocytes were metabolically labelled with 35S-methionine, and solubilized cell extracts were reacted with antibody to type VII collagen. The results indicate that the patient's keratinocytes synthesize type VII collagen and that the M(r) of the protein synthesized does not differ from that of an unaffected control. Because cultured cells from a patient severely affected with recessive dystrophic epidermolysis bullosa produce type VII collagen, the genetic defect, at least in this patient, is unlikely to reside in a major truncation of the type VII collagen molecule.

Lamina densa malformation involved in histogenesis of primary localized cutaneous amyloidosis

Skin lesions of lichenoid amyloidosis and macular amyloidosis were immunohistochemically investigated using five monoclonal antibodies against basement membrane zone (BMZ) components. A hemidesmosomal component did not contribute to amyloid deposits, but components of the lamina densa and anchoring fibrils were associated with amyloid deposits in the uppermost dermis. Immunoelectron microscopy revealed that these BMZ components were not only aggregated in the BMZ and dermis, but were also involved in the individual amyloid islets. The lamina densa was disrupted in the interface areas just above the amyloid deposits, where cytoplasm of the basal cells directly faced the aggregate of amyloid filaments. Aggregates of some BMZ components were continuous to the amyloid islets from the lamina densa area. These findings suggest that a lamina densa malformation is involved in amyloid production in the interface of the BMZ, and support the secretion theory rather than the fibrillar body theory of amyloidogenesis in these types of primary localized cutaneous amyloidosis.

Immunofluorescence on split skin for the detection and differentiation of basement membrane zone autoantibodies

The autoimmune subepidermal bullous diseases are characterized by autoantibodies to the basement membrane zone of stratified squamous epithelium. Recent studies have shown that the antibodies have characteristic ultrastructural and antigenic binding properties and that differentiating between those properties can be useful in distinguishing one disease from another. Immunofluorescence microscopy is widely used to detect basement membrane zone autoantibodies. The test has traditionally used tissue substrates with an intact basement membrane zone. Those substrates are limited because autoantibody binding cannot always be detected and because autoantibodies with different ultrastructural and antigenic binding properties cannot be distinguished from each other. Normal human skin that has been separated through the basement membrane zone (i.e., split skin) has recently been used as a substrate for detecting and characterizing basement membrane zone autoantibodies by immunofluorescence. Studies indicate that split skin is a more sensitive substrate than intact skin for detecting the antibodies and that antibodies with different ultrastructural binding sites can often be differentiated from one another on split skin. Those studies suggest split skin is the substrate of choice for the routine immunofluorescence evaluation of autoimmune subepidermal bullous diseases.

Autosomal dominant erythromelalgia

We present a kindred of 29 persons affected with erythromelalgia (erythermalgia) in 5 generations. This paper updates the family reported by Burbank et al. [1966]. Patients have symptoms of intermittent intense burning limb pain related to increased skin temperature. No successful treatment has been identified, and the pathogenetic mechanism has not been established. Most affected individuals are female.

Peripheral blood mononuclear cell subsets in patients with severe inherited forms of epidermolysis bullosa

BACKGROUND AND DESIGN

Epidermolysis bullosa (EB) is a group of inherited disorders in which slight trauma to the skin results in blister formation. Patients with severe types of EB suffer cutaneous infections that sometimes progress to septicemia and cutaneous and gastrointestinal carcinomas that are locally aggressive and frequently metastasize. Previous studies have shown deficits in natural killer (NK) cell activity as well as in lymphokine and monokine production in patients with severe forms of EB. Alterations in peripheral blood mononuclear cells, however, which may reflect on immune functions in patients with EB, have received little attention. A prospective study was designed to ascertain if differences existed between subsets of peripheral blood mononuclear cells in patients with severe forms of EB vs healthy control subjects. Thirty patients with clinical and histologic diagnoses of EB and 30 healthy volunteers were studied. Flow cytometric analysis of labeled cells was performed.

RESULTS

Absolute numbers of CD3+, CD2+, CD4+, CD19+, NK+, CD29+, and CD45R+ cells were lower in patients with severe types of EB in comparison with controls. The T cells showed decreased numbers of interleukin 2 receptors. An increase in numbers of CD20+, CD4+ CD8+, and CD4-CD8- cells was also observed in patients with severe types of EB.

CONCLUSION

Alterations in monocyte and lymphocyte subsets known to affect host immune response were observed in patients with severe forms of EB. Quantitative changes relative to controls included decreased total numbers of T cells with greater decreases in helper cells, decreased NK cells, and a diminished number of interleukin 2 receptors. Such changes have been associated previously with a lower resistance to infections and to neoplasia. The changes in subsets correlated with the severity of the cutaneous and extracutaneous disease in the patients with EB.

Extensive variant of cutaneous amyloidosis: report of a case with electron-microscopic and immunohistochemical studies of the basement membrane zone at sites of amyloid production

A 60-year-old Japanese female developed widespread lichenoid eruptions with pigmentation, which initially appeared in preceding erythematous skin lesions due to dermatomyositis. Thioflavine T and Dylon stainings, electron microscopy and immunohistochemistry revealed that thick amyloid deposits were present in the papillary dermis particularly beneath the epidermis. Autopsy showed no evidence of systemic amyloidosis. Electron microscopy of the lesional skin disclosed the disturbance of lamina densa formation in the epidermal basement membrane zone (BMZ). There was disruption and dissociation of the lamina densa from the basal cell, and a lamina-densa-like substance was found in the amyloid deposits. Immunofluorescence and immunoelectron microscopy showed that type IV and VII collagens, LDA-1 antigen (a noncollagenous component of the BMZ) and laminin were distributed in irregular thick deposits along the BMZ and were also present within the amyloid itself. These findings indicate that morphological and immunohistochemical abnormalities of the lamina densa may be involved in amyloid production at the interface of the epidermis and dermis, at least in this case.

Structure and antigenicity of the skin basement membrane zone

The skin basement membrane zone is comprised of two major ultrastructural regions, four associated structures, and at least 17 different antigens. In this brief review, the ultrastructure, antigenicity, and ontogeny of normal human skin will be discussed in detail, as will alterations in expression or immune response to selected basement membrane components in specific mechanobullous and autoimmune diseases.

Alpha-fetoprotein and acetylcholinesterase are not predictive of fetal junctional epidermolysis bullosa, Herlitz variant

Junctional epidermolysis bullosa, Herlitz variant (junctional EB-Herlitz) is a lethal autosomal recessive skin disorder currently amenable to prenatal diagnosis only by direct analysis of fetal skin. However, elevated levels of alpha-fetoprotein, as well as the presence of acetylcholinesterase in amniotic fluid, have been associated with other severe fetal genodermatoses. Fetal skin samplings were performed in ten pregnancies at risk for fetal junctional EB-Herlitz, with three fetuses affected on the basis of electron microscopic detection of blisters within the lamina lucida and abnormal hemidesmosomes. In neither affected nor unaffected pregnancies were maternal serum or amniotic fluid alpha-fetoprotein levels elevated. Moreover, alpha-fetoprotein levels in both maternal serum and amniotic fluid were not statistically different comparing affected and unaffected fetuses. Acetylcholinesterase was not present in the amniotic fluid samples of the three affected pregnancies. Unlike other severe fetal genodermatoses, neither alpha-fetoprotein nor acetylcholinesterase was predictive of junctional EB-Herlitz.