The Experts below are selected from a list of 7590 Experts worldwide ranked by ideXlab platform
R A J Eady - One of the best experts on this subject based on the ideXlab platform.
-
allelic heterogeneity of dominant and recessive col7a1 mutations underlying Epidermolysis bullosa pruriginosa
Journal of Investigative Dermatology, 1999Co-Authors: J E Mellerio, R A J Eady, John A Mcgrath, G H S Ashton, Rafik Mohammedi, Calum C Lyon, Brian Kirby, K E Harman, Julio Cesar Salasalanis, D J AthertonAbstract:The inherited mechanobullous disease, dystrophic Epidermolysis bullosa, is caused by type VII collagen gene (COL7A1) mutations. We studied six unrelated patients with a distinct clinical subtype of this disease, Epidermolysis bullosa pruriginosa, characterized by pruritus, excoriated prurigo nodules, and skin fragility. Mutation analysis using polymerase chain reaction amplification of genomic DNA, heteroduplex analysis and direct nucleotide sequencing demonstrated pathogenetic COL7A1 mutations in each case. Four patients had a glycine substitution mutation on one COL7A1 allele (G1791E, G2242R, G2369S, and G2713R), a fifth was a compound heterozygote for a splice site mutation (5532 + 1G-to-A) and a single base pair deletion (7786delG), and a sixth patient was heterozygous for an out-of-frame deletion mutation (6863del16). This study shows that the molecular pathology in patients with the distinctive clinical features of Epidermolysis bullosa pruriginosa is heterogeneous and suggests that other factors, in addition to the inherent COL7A1 mutation(s), may be responsible for an Epidermolysis bullosa pruriginosa phenotype.
-
Epidermolysis bullosa: hereditary skin fragility diseases as paradigms in cell biology
Archives of Dermatological Research, 1994Co-Authors: R A J Eady, M. G. S. DunnillAbstract:Recent research into the molecular basis of Epidermolysis bullosa has provided a unique insight into a variety of mechanisms in normal cell biology, such as cell-matrix interactions, and has uncovered an excellent model for studies on keratin intermediate filaments. The simplex forms of Epidermolysis bullosa are caused by mutations in the genes for the basal epidermal keratins, K5 and K14. Most mutations affect highly conserved parts of the molecules, illustrating their importance in normal keratin filament assembly and integrity. Mutations in corresponding regions of the differentiation-associated keratins, K1 and K10 can also occur in epidermolytic ichthyosis. Both recessive and dominant forms of dystrophic Epidermolysis bullosa result from mutations in an anchoring fibril collagen gene, COL7A1. Junctional Epidermolysis bullosa is caused by mutations in the genes encoding different chains of the novel laminin isoform, nicein/ kalinin, also known as laminin 5, which is associated with the anchoring filament-hemidesmosome complex of the basement membrane zone. These recent findings strengthen the evidence for the role of nicein/kalinin and type VII collagen in adherence and stabilization of the dermo-epidermal junction.
-
structural variations in anchoring fibrils in dystrophic Epidermolysis bullosa correlation with type vii collagen expression
Journal of Investigative Dermatology, 1993Co-Authors: John A Mcgrath, I M Leigh, Akemi Ishidayamamoto, Anthony Ogrady, R A J EadyAbstract:Dystrophic Epidermolysis bullosa is characterized by various abnormalities of anchoring fibrils, which are mainly composed of type VII collagen, at the dermal-epidermal junction. To define these changes more clearly, we examined skin samples from 22 patients with different forms of dystrophic Epidermolysis bullosa by pre-embedding immunoelectron microscopy using an antibody (LH 7:2) that binds to the NC-1 globular domain of type VII collagen, followed by 1 nm colloidal gold-labeled secondary antibodies and subsequent silver enhancement. In dominant dystrophic Epidermolysis bullosa cases, there was only a slight but variable reduction in the immunolabeling density on anchoring fibrils and on the lamina densa, in parts similar to normal human skin. In localized recessive dystrophic Epidermolysis bullosa skin, some fibrillar structures just below the lamina densa (and particularly subjacent to hemidesmosomes) had specific antibody labeling despite their lack of resemblance to definitive anchoring fibrils. Immunolabeling with LH 7:2 was also seen within basal keratinocyte endoplasmic reticulum and cytoplasmic vesicles in some dystrophic Epidermolysis bullosa patients, usually with milder phenotypic features. Even in the most severe cases of generalized recessive dystrophic Epidermolysis bullosa, occasional immunolabeling was found within the lamina densa and on scanty thin filamentous structures at sub-lamina densa sites usually occupied by anchoring fibrils. This study suggests that dystrophic Epidermolysis bullosa patients express some type VII collagen NC-1 domain epitopes that may be variably reduced at the dermal-epidermal junction or retained within basal keratinocytes. The clinical heterogeneity in dystrophic Epidermolysis bullosa is mirrored by a range of immunoelectron microscopy findings, indicating variability in completeness of anchoring fibril formation and a possible spectrum of underlying type VII collagen structural protein abnormalities.
-
a mutation in the conserved helix termination peptide of keratin 5 in hereditary skin blistering
Nature, 1992Co-Authors: E. B. Lane, A H M Heagerty, I M Leigh, Elizabeth L Rugg, Harshad Navsaria, Akemi Ishidayamamoto, R A J EadyAbstract:IN the hereditary blistering condition Epidermolysis bullosa simplex, the skin blisters on trauma following rupture of epidermal basal cells. Clinical variations range from severely incapacitating, especially in early childhood, to mild forms that may not even present clinically. Dowling–Meara Epidermolysis bullosa simplex is characterized by clusters of epidermal blisters and keratin clumping in the cytoplasm1; recent reports describe potentially causal mutations in keratin 14 (refs 2, 3). Here we describe a "complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction. The two conserved helix boundary peptides are predicted to be essential for filament assembly, and the requirement for two complementary (type I and type II) keratins is absolute. Epidermolysis bullosa simplex diseases demonstrate the function of the keratin cytoskeleton in resisting compaction stresses which otherwise lead to cell lysis.
-
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
Journal of The American Academy of Dermatology, 1991Co-Authors: Jo-david Fine, Lorraine Johnson, Eugene A. Bauer, Robert A. Briggaman, Karen A Holbrook, R A J Eady, Martin D Carter, Nancy B Esterly, Sidney Hurwitz, Andrew N LinAbstract:Abstract 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.
Dedee F Murrell - One of the best experts on this subject based on the ideXlab platform.
-
mutation analysis and characterization of col7a1 mutations in dystrophic Epidermolysis bullosa
Experimental Dermatology, 2008Co-Authors: Dedee F Murrell, Ningning DangAbstract:Dystrophic Epidermolysis bullosa (DEB) is inherited in both an autosomal dominant DEB and autosomal recessive manner RDEB, both of which result from mutations in the type VII collagen gene (COL7A1). To date, 324 pathogenic mutations have been detected within COL7A1 in different variants of DEB; many mutations are clustered in exon 73 (10.74%) which is close to the 39 amino acid interruption region. Dominant dystrophic Epidermolysis bullosa usually involves glycine substitutions within the triple helix of COL7A1 although other missense mutations, deletions or splice-site mutations may underlie some cases. In recessive dystrophic Epidermolysis bullosa, the mutations include nonsense, splice site, deletions or insertions, 'silent' glycine substitutions within the triple helix and non-glycine missense mutations within the triple helix or non-collagenous NC-2 domain. The nature of mutations in COL7A1 and their positions correlate reasonably logically with the severity of the resulting phenotypes.
-
keratin 14 point mutations at codon 119 of helix 1a resulting in different Epidermolysis bullosa simplex phenotypes
Journal of Investigative Dermatology, 2001Co-Authors: Rebecca E Cummins, S Klingberg, Dedee F Murrell, Julie Wesley, Maureen Rogers, Yali ZhaoAbstract:Epidermolysis bullosa simplex is a heterogeneous group of inherited bullous disorders due to mutations in keratins 5 and 14. We report two different mutations in keratin 14 at codon 119 of the helix initiation peptide, each with different phenotypic expression. One, a sporadic case that clinically resembles Dowling-Meara Epidermolysis bullosa simplex, resulted from conversion of methionine to threonine (M119T). The other, a multigeneration family with the Koebner phenotype, resulted from a previously unreported methionine to valine substitution (M119V). We suggest that loss of hydrophobicity during conversion of methionine to threonine is responsible for the more severe presentation of the first family, whereas maintenance of the hydrophobic nature of the amino acid with conversion to valine resulted in a less severe variant of Epidermolysis bullosa simplex. Although most prior mutations in the highly conserved boundary motif of the α-helix have resulted in the Dowling-Meara subtype, our findings confirm that it is not always possible to predict the Epidermolysis bullosa simplex severity on the basis of the location of the mutation along the keratin polypeptide. The specific amino acid substitution may be more critical in some cases.
Akemi Ishidayamamoto - One of the best experts on this subject based on the ideXlab platform.
-
targeted exon skipping restores type vii collagen expression and anchoring fibril formation in an in vivo rdeb model
Journal of Investigative Dermatology, 2016Co-Authors: Akemi Ishidayamamoto, Sandrina Turczynski, Matthias Titeux, Laure Tonasso, Audrey Decha, Alain HovnanianAbstract:Dystrophic Epidermolysis bullosa is a group of orphan genetic skin diseases dominantly or recessively inherited, caused by mutations in COL7A1 encoding type VII collagen, which forms anchoring fibrils. Individuals with recessive dystrophic Epidermolysis bullosa develop severe skin and mucosal blistering after mild trauma. The exon skipping strategy consists of modulating splicing of a pre-mRNA to induce skipping of a mutated exon. We have targeted COL7A1 exons 73 and 80, which carry recurrent mutations and whose excision preserves the open reading frame. We first showed the dispensability of these exons for type VII collagen function in vivo. We then showed that transfection of primary recessive dystrophic Epidermolysis bullosa keratinocytes and fibroblasts carrying null mutations in exon 73 and/or 80, with 2′- O -methyl antisense oligoribonucleotides, led to efficient ex vivo skipping of these exons (50–95%) and resulted in a significant level (up to 36%) of type VII collagen re-expression. Finally, one or two subcutaneous injections of antisense oligoribonucleotides at doses ranging from 400 μg up to 1 mg restored type VII collagen expression and anchoring fibril formation in vivo in a xenograft model of recessive dystrophic Epidermolysis bullosa skin equivalent. This work provides a proof of principle for the treatment of patients with recessive dystrophic Epidermolysis bullosa by exon skipping using subcutaneous administration of antisense oligoribonucleotides.
-
bone marrow transplantation for recessive dystrophic Epidermolysis bullosa
The New England Journal of Medicine, 2010Co-Authors: John E Wagner, Mark J Osborn, Akemi Ishidayamamoto, David T Woodley, Douglas R Keene, Mei Chen, Megan J Riddle, John A Mcgrath, Maria K Hordinsky, Troy C LundAbstract:Background Recessive dystrophic Epidermolysis bullosa is an incurable, often fatal mucocutaneous blistering disease caused by mutations in COL7A1, the gene encoding type VII collagen (C7). On the basis of preclinical data showing biochemical correction and prolonged survival in col7 −/− mice, we hypothesized that allogeneic marrow contains stem cells capable of ameliorating the manifestations of recessive dystrophic Epidermolysis bullosa in humans. Methods Between October 2007 and August 2009, we treated seven children who had recessive dystrophic Epidermolysis bullosa with immunomyeloablative chemotherapy and allogeneic stem-cell transplantation. We assessed C7 expression by means of immunofluorescence staining and used transmission electron microscopy to visualize anchoring fibrils. We measured chimerism by means of competitive polymerase-chain-reaction assay, and documented blister formation and wound healing with the use of digital photography. Results One patient died of cardiomyopathy before transpl...
-
structural variations in anchoring fibrils in dystrophic Epidermolysis bullosa correlation with type vii collagen expression
Journal of Investigative Dermatology, 1993Co-Authors: John A Mcgrath, I M Leigh, Akemi Ishidayamamoto, Anthony Ogrady, R A J EadyAbstract:Dystrophic Epidermolysis bullosa is characterized by various abnormalities of anchoring fibrils, which are mainly composed of type VII collagen, at the dermal-epidermal junction. To define these changes more clearly, we examined skin samples from 22 patients with different forms of dystrophic Epidermolysis bullosa by pre-embedding immunoelectron microscopy using an antibody (LH 7:2) that binds to the NC-1 globular domain of type VII collagen, followed by 1 nm colloidal gold-labeled secondary antibodies and subsequent silver enhancement. In dominant dystrophic Epidermolysis bullosa cases, there was only a slight but variable reduction in the immunolabeling density on anchoring fibrils and on the lamina densa, in parts similar to normal human skin. In localized recessive dystrophic Epidermolysis bullosa skin, some fibrillar structures just below the lamina densa (and particularly subjacent to hemidesmosomes) had specific antibody labeling despite their lack of resemblance to definitive anchoring fibrils. Immunolabeling with LH 7:2 was also seen within basal keratinocyte endoplasmic reticulum and cytoplasmic vesicles in some dystrophic Epidermolysis bullosa patients, usually with milder phenotypic features. Even in the most severe cases of generalized recessive dystrophic Epidermolysis bullosa, occasional immunolabeling was found within the lamina densa and on scanty thin filamentous structures at sub-lamina densa sites usually occupied by anchoring fibrils. This study suggests that dystrophic Epidermolysis bullosa patients express some type VII collagen NC-1 domain epitopes that may be variably reduced at the dermal-epidermal junction or retained within basal keratinocytes. The clinical heterogeneity in dystrophic Epidermolysis bullosa is mirrored by a range of immunoelectron microscopy findings, indicating variability in completeness of anchoring fibril formation and a possible spectrum of underlying type VII collagen structural protein abnormalities.
-
a mutation in the conserved helix termination peptide of keratin 5 in hereditary skin blistering
Nature, 1992Co-Authors: E. B. Lane, A H M Heagerty, I M Leigh, Elizabeth L Rugg, Harshad Navsaria, Akemi Ishidayamamoto, Robin A.j. EadyAbstract:IN the hereditary blistering condition Epidermolysis bullosa simplex, the skin blisters on trauma following rupture of epidermal basal cells. Clinical variations range from severely incapacitating, especially in early childhood, to mild forms that may not even present clinically. Dowling–Meara Epidermolysis bullosa simplex is characterized by clusters of epidermal blisters and keratin clumping in the cytoplasm1; recent reports describe potentially causal mutations in keratin 14 (refs 2, 3). Here we describe a "complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction. The two conserved helix boundary peptides are predicted to be essential for filament assembly, and the requirement for two complementary (type I and type II) keratins is absolute. Epidermolysis bullosa simplex diseases demonstrate the function of the keratin cytoskeleton in resisting compaction stresses which otherwise lead to cell lysis.
-
a mutation in the conserved helix termination peptide of keratin 5 in hereditary skin blistering
Nature, 1992Co-Authors: E. B. Lane, A H M Heagerty, I M Leigh, Elizabeth L Rugg, Harshad Navsaria, Akemi Ishidayamamoto, R A J EadyAbstract:IN the hereditary blistering condition Epidermolysis bullosa simplex, the skin blisters on trauma following rupture of epidermal basal cells. Clinical variations range from severely incapacitating, especially in early childhood, to mild forms that may not even present clinically. Dowling–Meara Epidermolysis bullosa simplex is characterized by clusters of epidermal blisters and keratin clumping in the cytoplasm1; recent reports describe potentially causal mutations in keratin 14 (refs 2, 3). Here we describe a "complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction. The two conserved helix boundary peptides are predicted to be essential for filament assembly, and the requirement for two complementary (type I and type II) keratins is absolute. Epidermolysis bullosa simplex diseases demonstrate the function of the keratin cytoskeleton in resisting compaction stresses which otherwise lead to cell lysis.
Jo-david Fine - One of the best experts on this subject based on the ideXlab platform.
-
inherited Epidermolysis bullosa recent basic and clinical advances
Current Opinion in Pediatrics, 2010Co-Authors: Jo-david FineAbstract:Purpose of reviewThis review highlights key findings, both clinical and basic, that have been published in the field of inherited Epidermolysis bullosa within the past few years.Recent findingsNew Epidermolysis bullosa phenotypes, genotypes and modes of transmission have been identified, resulting i
-
pseudosyndactyly and musculoskeletal contractures in inherited Epidermolysis bullosa experience of the national Epidermolysis bullosa registry 1986 2002
Journal of Hand Surgery (European Volume), 2005Co-Authors: Jo-david Fine, Lorraine Johnson, Madeline Weiner, Joy Deleoz, David T Devries, Sydney S Cash, Amy Stein, Chirayath M. SuchindranAbstract:Mitten deformities of the hands and feet occur in nearly every patient with the most severe subtype (Hallopeau-Siemens) of recessive dystrophic Epidermolysis bullosa, and in at least 40–50% of all other recessive dystrophic Epidermolysis bullosa patients. Smaller numbers of patients with dominant dystrophic, junctional, and simplex types of Epidermolysis bullosa are also at risk of this complication. Surgical intervention is commonly performed to correct these deformities, but recurrence and the need for repeated surgery are common. Higher numbers of Epidermolysis bullosa patients also develop musculoskeletal contractures in other anatomic sites, further impairing overall function. Lifetable analyses not only better project the cumulative risk of mitten deformities and other contractures but also emphasize the need for early surveillance and intervention, since both of these musculoskeletal complications may occur within the first year of life.
-
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
Journal of The American Academy of Dermatology, 1991Co-Authors: Jo-david Fine, Lorraine Johnson, Eugene A. Bauer, Robert A. Briggaman, Karen A Holbrook, R A J Eady, Martin D Carter, Nancy B Esterly, Sidney Hurwitz, Andrew N LinAbstract:Abstract 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.
John A Mcgrath - One of the best experts on this subject based on the ideXlab platform.
-
the three body problem of therapy with induced pluripotent stem cells
Genome Medicine, 2015Co-Authors: Jakub Tolar, John A McgrathAbstract:Regenerative medicine has a three-body problem: alignment of the dynamics of the genome, stem cell and patient. Focusing on the rare inherited fragile skin disorder Epidermolysis bullosa, three recent innovative studies have used induced pluripotent stem cells and gene correction, revertant mosaicism or genome editing to advance the prospects of better cell-based therapeutics to restore skin structure and function for Epidermolysis bullosa and potentially other inherited diseases.
-
bone marrow transplantation for recessive dystrophic Epidermolysis bullosa
The New England Journal of Medicine, 2010Co-Authors: John E Wagner, Mark J Osborn, Akemi Ishidayamamoto, David T Woodley, Douglas R Keene, Mei Chen, Megan J Riddle, John A Mcgrath, Maria K Hordinsky, Troy C LundAbstract:Background Recessive dystrophic Epidermolysis bullosa is an incurable, often fatal mucocutaneous blistering disease caused by mutations in COL7A1, the gene encoding type VII collagen (C7). On the basis of preclinical data showing biochemical correction and prolonged survival in col7 −/− mice, we hypothesized that allogeneic marrow contains stem cells capable of ameliorating the manifestations of recessive dystrophic Epidermolysis bullosa in humans. Methods Between October 2007 and August 2009, we treated seven children who had recessive dystrophic Epidermolysis bullosa with immunomyeloablative chemotherapy and allogeneic stem-cell transplantation. We assessed C7 expression by means of immunofluorescence staining and used transmission electron microscopy to visualize anchoring fibrils. We measured chimerism by means of competitive polymerase-chain-reaction assay, and documented blister formation and wound healing with the use of digital photography. Results One patient died of cardiomyopathy before transpl...
-
comparative mutation detection screening of the type vii collagen gene col7a1 using the protein truncation test fluorescent chemical cleavage of mismatch and conformation sensitive gel electrophoresis
Journal of Investigative Dermatology, 1999Co-Authors: Robin A.j. Eady, J E Mellerio, G H S Ashton, Rafik Mohammedi, Neil V Whittock, Christopher G Mathew, Stephen J Abbs, John A McgrathAbstract:Mutations in the type VII collagen gene, COL7A1, give rise to the blistering skin disease, dystrophic Epidermolysis bullosa. We have developed two new mutation detection strategies for the screening of COL7A1 mutations in patients with dystrophic Epidermolysis bullosa and compared them with an established protocol using conformational sensitive gel electrophoresis. The first strategy consisted of an RNA based protein truncation test that amplified the entire coding region in only four overlapping nested reverse transcriptase-polymerase chain reaction assays. These fragments were transcribed and translated in vitro and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We have used the protein truncation test procedure to characterize 15 truncating mutations in 13 patients with severe recessive dystrophic Epidermolysis bullosa yielding a detection sensitivity of 58%. The second strategy was a DNA-based fluorescent chemical cleavage of mismatch (fl-CCM) procedure that amplified the COL7A1 gene in 21 polymerase chain reaction assays. Mismatches, formed between patient and control DNA, were identified using chemical modification and cleavage of the DNA. We have compared fl-CCM with conformational sensitive gel electrophoresis by screening a total of 50 dominant and recessive dystrophic Epidermolysis bullosa patients. The detection sensitivity for fl-CCM was 81% compared with 75% for conformational sensitive gel electrophoresis (p = 0.37 χ2-test). Using a combination of the three techniques we have screened 93 dystrophic Epidermolysis bullosa patients yielding an overall sensitivity of 87%, detecting 79 different mutations, 57 of which have not been reported previously. Comparing all three approaches, we believe that no single method is consistently better than the others, but that the fl-CCM procedure is a sensitive, semiautomated, high throughput system that can be recommended for COL7A1 mutation detection.
-
allelic heterogeneity of dominant and recessive col7a1 mutations underlying Epidermolysis bullosa pruriginosa
Journal of Investigative Dermatology, 1999Co-Authors: J E Mellerio, R A J Eady, John A Mcgrath, G H S Ashton, Rafik Mohammedi, Calum C Lyon, Brian Kirby, K E Harman, Julio Cesar Salasalanis, D J AthertonAbstract:The inherited mechanobullous disease, dystrophic Epidermolysis bullosa, is caused by type VII collagen gene (COL7A1) mutations. We studied six unrelated patients with a distinct clinical subtype of this disease, Epidermolysis bullosa pruriginosa, characterized by pruritus, excoriated prurigo nodules, and skin fragility. Mutation analysis using polymerase chain reaction amplification of genomic DNA, heteroduplex analysis and direct nucleotide sequencing demonstrated pathogenetic COL7A1 mutations in each case. Four patients had a glycine substitution mutation on one COL7A1 allele (G1791E, G2242R, G2369S, and G2713R), a fifth was a compound heterozygote for a splice site mutation (5532 + 1G-to-A) and a single base pair deletion (7786delG), and a sixth patient was heterozygous for an out-of-frame deletion mutation (6863del16). This study shows that the molecular pathology in patients with the distinctive clinical features of Epidermolysis bullosa pruriginosa is heterogeneous and suggests that other factors, in addition to the inherent COL7A1 mutation(s), may be responsible for an Epidermolysis bullosa pruriginosa phenotype.
-
structural variations in anchoring fibrils in dystrophic Epidermolysis bullosa correlation with type vii collagen expression
Journal of Investigative Dermatology, 1993Co-Authors: John A Mcgrath, I M Leigh, Akemi Ishidayamamoto, Anthony Ogrady, R A J EadyAbstract:Dystrophic Epidermolysis bullosa is characterized by various abnormalities of anchoring fibrils, which are mainly composed of type VII collagen, at the dermal-epidermal junction. To define these changes more clearly, we examined skin samples from 22 patients with different forms of dystrophic Epidermolysis bullosa by pre-embedding immunoelectron microscopy using an antibody (LH 7:2) that binds to the NC-1 globular domain of type VII collagen, followed by 1 nm colloidal gold-labeled secondary antibodies and subsequent silver enhancement. In dominant dystrophic Epidermolysis bullosa cases, there was only a slight but variable reduction in the immunolabeling density on anchoring fibrils and on the lamina densa, in parts similar to normal human skin. In localized recessive dystrophic Epidermolysis bullosa skin, some fibrillar structures just below the lamina densa (and particularly subjacent to hemidesmosomes) had specific antibody labeling despite their lack of resemblance to definitive anchoring fibrils. Immunolabeling with LH 7:2 was also seen within basal keratinocyte endoplasmic reticulum and cytoplasmic vesicles in some dystrophic Epidermolysis bullosa patients, usually with milder phenotypic features. Even in the most severe cases of generalized recessive dystrophic Epidermolysis bullosa, occasional immunolabeling was found within the lamina densa and on scanty thin filamentous structures at sub-lamina densa sites usually occupied by anchoring fibrils. This study suggests that dystrophic Epidermolysis bullosa patients express some type VII collagen NC-1 domain epitopes that may be variably reduced at the dermal-epidermal junction or retained within basal keratinocytes. The clinical heterogeneity in dystrophic Epidermolysis bullosa is mirrored by a range of immunoelectron microscopy findings, indicating variability in completeness of anchoring fibril formation and a possible spectrum of underlying type VII collagen structural protein abnormalities.