Cases reported "Epidermolysis Bullosa"

Filter by keywords:



Filtering documents. Please wait...

1/16. Hemizygosity for a glycine substitution in collagen XVII: unfolding and degradation of the ectodomain.

    Defects of collagen XVII, a keratinocyte adhesion protein, are associated with epidermal detachment in junctional epidermolysis bullosa. Although some missense mutations in the collagen XVII gene COL17A1 have been described, the molecular mechanisms leading to disease have remained elusive in these cases. Here we assessed the biologic consequences of a missense mutation by studying the folding and stability of wild-type and mutated recombinant collagen XVII domains. The mutation occurred in a junctional epidermolysis bullosa patient who was compound heterozygous for the novel glycine substitution mutation G633D and the novel nonsense mutation R145X. collagen XVII mRNA was significantly reduced, indicating nonsense-mediated mRNA degradation and hemizygosity of the patient for the G633D substitution. As glycine residues within the collagen triple helices are important for stable conformation, the thermal stability of the wild-type and mutated eukaryotic recombinant Col15 domain of collagen XVII was assessed. The stability of the mutated fragment was clearly reduced. The midpoint of the helix-to-coil transition, Tm, was 5 degrees C lower than that of wild-type rCol15, indicating abnormal triple-helix folding and susceptibility to proteolysis. Consistently, immunoassays demonstrated reduced amounts of the full-length collagen XVII and absence of the soluble ectodomain in keratinocyte cultures, and lack of the ectodomain from the junctional epidermolysis bullosa skin. These observations show that the glycine substitution G633D in collagen XVII causes abnormal folding and susceptibility to degradation, and thus perturbs the physiologic adhesive functions of collagen XVII in the skin.
- - - - - - - - - -
ranking = 1
keywords = culture
(Clic here for more details about this article)

2/16. Truncated typeXVII collagen expression in a patient with non-herlitz junctional epidermolysis bullosa caused by a homozygous splice-site mutation.

    SUMMARY: Type XVII collagen (180-kDa bullous pemphigoid antigen) is a structural component of hemidesmosomes. Mutations in the type XVII collagen gene (COL17A1) have been established to be the molecular basis of non-Herlitz junctional epidermolysis bullosa (JEB-nH), an inherited skin blistering disorder. Here we report for the first time truncated type XVII collagen expression, caused by homozygosity for a COL17A1 donor splice-site mutation (4261 1 g --> c), which was identified by PCR amplification on genomic dna. By RT-PCR and sequencing of cDNA derived from mRNA from the patient's cultured keratinocytes, we provide evidence of cryptic splicing and exon skipping, most abundantly of exon 52. JEB-nH patients with COL17A1 splice-site mutations resulting in an exon skip often have no immunologically detectable type XVII collagen. However, in our patient with the generalized atrophic benign epidermolysis bullosa subtype, a small amount of type XVII collagen was detectable in the skin, and immunoblotting of cultured keratinocytes revealed that the 180-kDa protein was 10 kDa shorter. We hypothesize that the function of this truncated type XVII collagen polypeptide, which is expressed at low levels, is impaired, explaining the JEB-nH phenotype.
- - - - - - - - - -
ranking = 2
keywords = culture
(Clic here for more details about this article)

3/16. Novel mutations in the LAMC2 gene in non-Herlitz junctional epidermolysis bullosa: effects on laminin-5 assembly, secretion, and deposition.

    laminin-5 is the major adhesion ligand of epithelial cells. Mutations in the three genes (LAMA3, LAMB3, LAMC2) encoding the laminin-5 chains cause junctional epidermolysis bullosa, a clinically and genetically heterogeneous blistering skin disease. Here, we describe a non-Herlitz junctional epidermolysis bullosa patient, compound heterozygote for two novel mutations affecting the LAMC2 gene. The mutation in the paternal allele is a de novo splice site mutation (522-1G-->A) that results in in-frame skipping of exon 4 and synthesis of a mutated gamma2 polypeptide (gamma2Delta4) carrying a 33 amino acid deletion within the N-terminal domain V. The maternal mutation is a one base pair insertion (3511insA) in the 3' terminal exon of LAMC2 resulting in a frameshift and a premature termination codon. mutation 3511insA is predicted to lead to the synthesis of a gamma2 polypeptide (gamma2t) disrupted in its alpha-helical C-terminal structure and truncated of the last 25 amino acids. keratinocytes isolated from the patient's skin showed a markedly decreased level of gamma2 chain mRNA and secreted scant amounts of laminin-5, which undergoes physiologic proteolytic processing. To investigate the biologic function of the laminin-5 molecules synthesized by the patient, mutant gamma2 cDNAs were transiently expressed in gamma2-null keratinocytes. transfection of the gamma2Delta4 cDNA resulted in restoration of laminin-5 deposition onto the culture substrate, which demonstrates that the gamma2 polypeptides carrying a deletion in domain V, upstream of the gamma2 proteolytic cleavage site, are assembled into native laminin-5 that is secreted and extracellularly processed. In contrast, transfection of a mutant cDNA expressing the gamma2t chain failed to restore laminin-5 immunoreactivity, which indicates that integrity of the gamma2 C-terminal amino acid sequences is required for laminin-5 assembly. These results correlate for the first time a functional alteration in a laminin-5 domain with a mild junctional epidermolysis bullosa phenotype.
- - - - - - - - - -
ranking = 1
keywords = culture
(Clic here for more details about this article)

4/16. Use of skin substitutes in pediatric patients.

    There are various artificial skin substitutes available commercially. The authors have used Integra, cultured epithelium, and Apligraf in their clinic. In the present report, they present their experiences based on two case reports. The first patient was a 12-year-old boy with widespread skin defects and left axillary contracture due to epidermolysis bullosa (EB). Apligraf was used to cover the skin defects on the trunk and face and to manage ectropion and axillary contracture. The second patient was a 6-year-old boy who suffered neurocutaneous melanosis. Partial excision of a pigmented lesion on the back created a large defect. Integra application followed by repair with cultured autologous skin was accomplished, and the results were satisfactory. skin substitute products 1) are commercially immediately available; 2) are effective for management of contractures, chronic wounds, and chronic skin illnesses; 3) decrease or avoid the risk of donor area morbidity, which is more difficult to treat in children; 4) provide long-term coverage of the wound; and 5) can be used in conjunction with autologous tissue (e.g., Integra followed by cultured epithelium applications).
- - - - - - - - - -
ranking = 3
keywords = culture
(Clic here for more details about this article)

5/16. Treatment of chronic erosions of junctional epidermolysis bullosa with human epidermal allografts.

    We have successfully treated chronic central facial erosions of a patient with junctional epidermolysis bullosa using cultured epidermal allografts. keratinocytes isolated from a skin biopsy of the patient's biological mother were used to generate the epidermal allografts. Significant re-epithelialization occurred during the course of four grafting procedures. Cultured epidermal allografts appear to be a promising method for treatment of chronic erosions of junctional epidermolysis bullosa.
- - - - - - - - - -
ranking = 1
keywords = culture
(Clic here for more details about this article)

6/16. Herpetic infection in epidermolysis bullosa.

    patients with various forms of epidermolysis bullosa have fragile skin which can act as a breeding ground for multiple microbial agents. Standard wound care practices advocate the use of special dressings on open erosions as well as antibiotic topical medications to treat and prevent cutaneous infections. We report a child with recessive dystrophic epidermolysis bullosa admitted to our institution because of fevers at home. She was treated with multiple antibiotics for a cutaneous infection of the right hand. During her hospital stay, she sustained persistent fevers, and oral erosions developed, with progressive hemorrhagic crusting. Viral culture of the lip grew herpes simplex virus type 1, consistent with a diagnosis of herpetic gingivostomatitis. We present this patient to illustrate the importance of investigating wounds of epidermolysis bullosa patients for viral agents when faced with managing a child with an unclear source of fever. To the best of our knowledge, although this is the first report of herpetic gingivostomatitis in association with epidermolysis bullosa, it is likely to be more prevalent than the literature could suggest.
- - - - - - - - - -
ranking = 1
keywords = culture
(Clic here for more details about this article)

7/16. collagen biosynthesis in a case of epidermolysis bullosa dystrophica recessiva.

    collagen metabolism was studied in fibroblast cultures from a patient presenting an epidermolysis bullosa dystrophica recessiva (EBDR) syndrome characterized, in particular, by blistering below the basal lamina observed by electron microscopy. The previously described increase in collagen production was confirmed and several other qualitative modifications of the secreted collagen were observed, including an underhydroxylation of lysine, a decrease in the type III/type I collagen ratio, and an increase in the rapidly degraded collagen. On the other hand, these fibroblasts were able to organize and contract collagen to form a dermal equivalent like normal fibroblasts. Normal keratinocytes can grow and form an epidermal sheet on the surface of these dermal equivalents including normal or pathological fibroblasts.
- - - - - - - - - -
ranking = 1
keywords = culture
(Clic here for more details about this article)

8/16. Antenatal diagnosis of recessive dystrophic epidermolysis bullosa: collagenase expression in cultured fibroblasts as a biochemical marker.

    We performed fetoscopy and skin biopsy on a 19-week fetus at risk for recessive dystrophic epidermolysis bullosa (RDEB). Ultrastructural analysis of the tissue revealed dermolytic blister formation in the skin characteristic of the disease. To develop a biochemical test for use in antenatal diagnosis of RDEB, we established skin fibroblast cultures from the 20-week aborted fetus. The collagenase production by fetal RDEB fibroblast cultures was greater than seen in normal fetal fibroblast cultures. The concentration in culture medium from fetal RDEB cultures was 5.42 /- 0.74 micrograms/ml (mean /- SE) compared with 2.24 /- 1.11 micrograms/ml in normal adult control cultures and 2.05 /- 0.61 micrograms/ml in cultures from patients with other genetic forms of epidermolysis bullosa (p less than 0.025). In contrast, the concentration of collagenase in the fetal RDEB culture medium was not different from that seen in cell cultures from known patients with RDEB (5.34 /- 1.12 micrograms/ml). Collagenase activity of the fetal RDEB medium was also increased approximately 3.5-fold. These data indicate that enhanced expression of collagenase by fetal RDEB skin fibroblasts can serve as a biochemical adjunct, and possibly an alternative, to morphologic examination of tissue for antenatal diagnosis.
- - - - - - - - - -
ranking = 13
keywords = culture
(Clic here for more details about this article)

9/16. Treatment of junctional epidermolysis bullosa with epidermal autografts.

    We have successfully treated chronic facial erosions in three boys with junctional epidermolysis bullosa. In each patient, keratinocytes were harvested from the roof of suction blisters created on clinically uninvolved skin. They were grown in tissue culture on collagen sponges and grafted onto facial erosions that were previously treated with 2% mupirocin ointment. This experimental antibiotic ointment has proved efficacy in eradicating cutaneous pathogens such as staphylococcus aureus from chronic wounds. In two patients, complete reepithelialization was achieved over 7 and 10 months, respectively, and partial reepithelialization occurred in another patient in whom treatment is ongoing. Epidermal autografts are a promising means for improving function and appearance in eroded skin caused by junctional epidermolysis bullosa.
- - - - - - - - - -
ranking = 1
keywords = culture
(Clic here for more details about this article)

10/16. Proteases are responsible for blister formation in recessive dystrophic epidermolysis bullosa and epidermolysis bullosa simplex.

    The specific factors which induce blister formation in recessive dystrophic epidermolysis bullosa (RDEB) and epidermolysis bullosa simplex (EBS) were studied by culturing normal human skin with blister fluid from patients with RDEB and EBS. When skin from a healthy person was cultured with RDEB blister fluid, it developed a clean subepidermal blister with histology similar to that of a RDEB blister. The specific factor(s) which induced this subepidermal blister was inactivated by heat (60 degrees C, 30 min), trypsin digestion and by treating with EDTA, EGTA, alpha 2-macroglobulin, soybean trypsin inhibitor (SBTI) or N-ethylmaleimide (NEM), but was not affected by dialysis. These findings suggest that the active factor(s) in the blister fluid from patients with RDEB might include collagenase, neutral thiol protease and trypsin-like protease. By contrast, when normal skin was cultured with EBS blister fluid, this produced a clean intra-epidermal blister with histology similar to that of an EBS blister. The specific factor(s) inducing the intra-epidermal blister was inactivated by heat (60 degrees C, 30 min), trypsin digestion and by treating with NEM, but was not affected by dialysis, divalent cation chelators (EGTA, EDTA), alpha 2-macroglobulin, SBTI and pepstatin. These results suggest that the active factor(s) inducing the intra-epidermal blister in EBS might be a neutral SH-protease.
- - - - - - - - - -
ranking = 2
keywords = culture
(Clic here for more details about this article)
| Next ->


Leave a message about 'Epidermolysis Bullosa'


We do not evaluate or guarantee the accuracy of any content in this site. Click here for the full disclaimer.