Approaches to the study of epidermolysis bullosa

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.

The musculoskeletal manifestations of epidermolysis bullosa: an analysis of 19 cases with a review of the literature

Epidermolysis bullosa encompasses a group of rare disorders characterized by marked skin fragility and blister formation. In patients with dystrophic epidermolysis bullosa, skeletal and soft-tissue abnormalities are an important feature. An analysis of the musculoskeletal manifestations in 19 patients is presented. In the hands and feet, features included generalized osteoporosis, wedge-shaped thinning and hooking of distal phalanges, overconstricted bones, acro-osteolysis, flexion contractures, metatarsal and metacarpal subluxation, distal trophic changes, webbing of digits, encasement of the whole extremity in a pouch of skin, soft-tissue calcification and retarded skeletal maturity. Previously undescribed findings in the hands and feet are bony ankylosis of the proximal interphalangeal joints, resorption of the metatarsal and metacarpal heads, shortened metatarsal bones, carpal and tarsal fusion and destruction, and cystic changes of the distal radius and ulna. In the remainder of the skeleton, hip dysplasia with premature osteoarthritis, knee joint bony ankylosis and thoracic and thoraco-lumbar scoliosis are other undescribed findings.

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.

Revised clinical and laboratory criteria for subtypes of inherited epidermolysis bullosa. A consensus report by the Subcommittee on Diagnosis and Classification of the National Epidermolysis Bullosa Registry

Inherited epidermolysis bullosa encompasses a number of diseases, with the common finding of blister formation after minor mechanical trauma to the skin. In some forms significant, if not eventually fatal, extracutaneous disease activity may occur. In recent years application of newer technologies has contributed substantially to an overall understanding of this collection of inherited diseases. Concurrently, many new phenotypes have been recognized, in part the result of ongoing prospective patient registries in the United States and abroad. Unfortunately, this has resulted in a massive literature that may appear to be confounded by seemingly excessive or arbitrary subdivision of epidermolysis bullosa variants. With these concerns in mind a subcommittee was established by the National Epidermolysis Bullosa Registry to summarize the current literature and to make recommendations as to the best clinical and laboratory criteria for the practical diagnosis and subclassification of patients with inherited epidermolysis bullosa.

Applicability of 19-DEJ-1 monoclonal antibody for the prenatal diagnosis or exclusion of junctional epidermolysis bullosa

Recently a monoclonal antibody (19-DEJ-1) was produced with binding specificity for the mid-lamina lucida of the skin dermo-epidermal junction, in very close association with overlying hemidesmosomes. Since skin cleavage occurs within the lamina lucida in the inherited blistering disorder, junctional epidermolysis bullosa (EB), and is associated with aberrations in the morphology and/or number of hemidesmosomes in such tissue, we have sought to determine whether this monoclonal antibody could be used for prenatal diagnosis. Fetoscopy-directed skin biopsies were obtained from two fetuses at risk for junctional EB and post-mortem samples from two other fetuses with the Herlitz type of junctional EB, the latter after prenatal diagnosis by electron microscopy and termination of each pregnancy. Specimens were examined in part by light and electron microscopy for evidence of skin cleavage or other alterations in morphology, and in part by indirect immunofluorescence for altered basement membrane antigenicity. Three of four fetuses were shown to have intra-lamina lucida blister formation indicative of, and hemidesmosome hypoplasia proving, junctional EB. Each was also shown to lack expression of GB3 and 19-DEJ-1 antigens, consistent with findings noted postnatally in junctional EB; diagnosis was confirmed in each at the time of therapeutic abortion. A fourth fetus had no abnormalities detected; lack of disease involvement was confirmed at the time of delivery, and subsequently over 8 months of careful serial evaluation. We conclude that 19-DEJ-1 monoclonal antibody is an accurate and sensitive immunohistochemical probe for junctional EB, and may be employed in the prenatal diagnostic evaluation of fetuses at risk for this disorder.

The eye in dystrophic epidermolysis bullosa: clinical and immunopathological findings

The ocular findings in a series of patients with dystrophic epidermolysis bullosa are presented. An immunopathological technique using monoclonal antibodies for examining components of the epithelial basement membrane of the conjunctiva is described and the results obtained on a conjunctival biopsy from a patient with dystrophic epidermolysis bullosa are presented.

Prenatal diagnosis of dominant and recessive dystrophic epidermolysis bullosa: application and limitations in the use of KF-1 and LH 7:2 monoclonal antibodies and immunofluorescence mapping technique

Prenatal diagnosis is now possible for junctional and recessive dystrophic forms of epidermolysis bullosa (EB); however, there is no similar published experience for dominant dystrophic EB, although data with KF-1 monoclonal antibody suggests that both forms of dystrophic EB can be identified at least postnatally with this unique probe. We now report our experience with light microscopy, electron microscopy, immunofluorescence mapping, and KF-1 and LH 7:2 monoclonal antibodies, in both a mother with dominant dystrophic EB and her fetus at risk, and in a fetus previously shown to be affected with recessive dystrophic EB. KF-1 and LH 7:2 antigens were absent in recessive dystrophic EB fetal skin, identical to findings observed postnatally. LH 7:2 was normally expressed in a mother with dominant dystrophic EB and in her fetus at risk for this disease. In contrast, while KF-1 antigen was abnormally expressed in the affected mother, it was normally expressed in only 1/7 fetal biopsies despite the fact that this fetus was shown by light and electron microscopy and immunofluorescence mapping to be unaffected with dominant dystrophic EB. We conclude that 1) transmission electron microscopy can be used to prenatally exclude the diagnosis of dominant dystrophic EB (Cockayne-Touraine variety), 2) immunofluorescence mapping is an accurate technique for prenatal as well as postnatal diagnosis of EB, and 3) KF-1 cannot by itself be used as an accurate probe for the prenatal diagnosis of dominant dystrophic EB, due to the apparent variability in the time for the normal expression of KF-1 in fetal skin during the second trimester.

Ultrastructure of first trimester chorionic villi with regard to the prenatal diagnosis of genodermatoses

Hopes are held out for chorion villus sampling, a technique which is gaining more and more importance for the first trimester prenatal diagnosis of chromosomal aberrations and metabolic abnormalities. A variety of inherited skin diseases can be diagnosed postnatally and prenatally (in the second trimester) by ultrastructural diagnostic markers. For evaluation of prenatal diagnosis in the first trimester, we investigated chorionic villi derived from the trophoblast layer of the early pregnancy by light microscopy and conventional electron microscopy. The ultrastructure of the cellular layers covering the villi, i.e., the inner cytotrophoblast and the outer syncytiotrophoblast, as well as that of the connective tissue of the inner extraembryonic mesoderm, are thoroughly described in relation to the ultrastructural changes in certain genodermatoses including epidermolyses and keratinization disorders. We found that chorionic villi have only a few of the characteristics differentiated in skin, and none of the structures which are relevant to the diagnosis of genodermatoses. In our view, the ultrastructural approach is not suitable for first trimester prenatal diagnosis of genodermatoses in chorionic villi.