Epidermolysis Bullosa Simplex Dowling-Meara Research Articles

586 New class of mTOR inhibitor stabilizes intermediate filament networks in severe epidermolysis bullosa simplex keratinocytes

Epidermolysis Bullosa Simplex (EBS) is a rare genodermatosis caused by mutations in either KRT5 or KRT14. Severe EBS (i.e., EBS Dowling-Meara) is characterized by extremely fragile skin with frequent and severe herpetiform blistering. Genetic mutations cause poor keratin 5/14 dimerization resulting in mechanically weakened intermediate filament (IF) networks that collapse into intracellular aggregates upon stress (e.g., scratching, UV). Enhanced cellular removal and degradation of mutant keratins through stimulation of autophagy and the UPS system has the potential to strengthen the IF networks, reducing blistering and erosions. Previously, UPS cochaperones (e.g., 4-phenylbuterate) were shown to decreased keratin aggregation but also decreased keratinocyte adhesion and migration. The purpose of this research was to evaluate if BM-3103, (4-Hydroxy 4'-methyoxytolan), a known wound healing promoter, anti-inflammatory, and autophagy inducer, could remove mutant keratins/aggregates thereby strengthening the IF network without adversely affecting cell survival, adhesion, or migration. Assays tested on patient derived EBS keratinocytes included: (1) Assessment of cytotoxicity, adhesion, and migration effects of BM-3103 using MTT, LDH, and scratch assays. (2) Autophagy induction (LC3-II conversion) and keratin aggregation (heat stress assay). There were no signs of cytotoxicity, loss of cell adhesion or slowed migration. Cells were exposed to escalating concentrations of BM-3103 for 24 hrs then heat shocked (43°C for 30min) generating an abundance of aggregates visualized by immunofluorescent microscopy. Untreated keratinocytes displayed keratin aggregate formation in 72% of KRT5 and 87% of KRT14 mutant cells. Treatment with BM-3103 reduced the incidence of keratin aggregates to 16% (p<0.01) of KRT5 and 24% (p<0.01) KRT14 mutant cells. BM-3103 is the first compound identified that is capable of stabilizing IF networks in keratinocytes from severe EBS patients. A clinical trial is ongoing to assess if BM-3103, can heal blistering areas and strengthen EBS patient skin.

A Novel Mutation of KRT14 Gene in a Newborn with Epidermolysis Bullosa Simplex (Dowling-Meara Type): Case Report

Epidermolysis bullosa simplex (EBS) is a group of inherited skin diseases characterized by intraepidermal blistering upon mild trauma. They are classified into three major types based on the severity and distribution of blisters, age of onset, and histological findings. These three major types are caused by KRT5 and KRT14 gene mutations. EBS Dowling-Meara (DM) is one of the most severe subtypes which mostly affects neonates. Electron microscopy is a primary diagnostic tool for EBS; however, mutation analysis has recently become more important for its diagnosis, prognosis, genetic counselling, and prenatal diagnosis. Several studies have reported that almost all mutations in EBS-DM patients are found in the highly conserved rod domains of the KRT5 and KRT14 genes and have also demonstrated a genotype-phenotype correlation. Here, we report an EBS-DM case diagnosed by mutation analysis in a newborn and a missense mutation not identified in humans previously.

Induced pluripotent stem cell (iPSC) line from an epidermolysis bullosa simplex patient heterozygous for keratin 5 E475G mutation and with the Dowling Meara phenotype

We have generated MLi002-A, a new induced pluripotent stem cell (iPSC) line derived from keratinocytes of a skin punch biopsy of a female patient with the severe epidermolysis bullosa simplex Dowling-Meara phenotype and the keratin K5 E475G mutation. Keratinocytes were reprogrammed using non-integrating Sendai virus vectors, and xeno-free culture conditions were used throughout. The characterization of MLi002-A cell line consisted of molecular karyotyping, mutation screening using restriction enzyme digestion and Sanger sequencing, and testing of the pluripotency and differentiation potentials by immunofluorescence of associated markers both in vitro and in vivo. This is the first iPSC model of EB Simplex.

Epidermolysis bullosa Simplex-Dowling–Meara mimicking epidermolysis bullosa simplex with mottled pigmentation

Epidermolysis bullosa simplex-Dowling–Meara (EBS-DM) variant is an autosomal dominant blistering genodermatosis due to mutations in genes coding for keratin 5 (K5) or keratin 14 (K14), specifically at the rod domain. Postinflammatory dyspigmentation can arise at sites of blistering, sometimes in a reticulate or mottled configuration. This mimics EBS with mottled pigmentation (EBS-MP), usually due to mutation in the head domain of K5, for which the pigmentation is not preceded by blisters. We report a case of an adult Malay male with recurrent blisters and mottled hyperpigmentation over his trunk and limbs, consistent with EBS-DM clinically, and confirmed on genetic mutation sequencing. Different K5 or K14 mutations, by altering keratinocyte adhesion and interfering with melanin pigment transport, can lead to variable phenotypes of skin fragility and/or hyperpigmentation, possibly modulated by other genetic or environmental factors.

Nursing Management of a Young Child With Epidermolysis Bullosa Simplex

Background Epidermolysis bullosa simplex (EBS) belongs to a group of inherited, mechanobullous disorders; one subtype is EBS Dowling–Meara (EBS-DM), which is the focus of this article. EBS-DM is characterized by painful skin blistering from minor friction, which evolves into chronic wounds. Objective We describe the holistic nursing care of a child with EBS-DM in a tertiary outpatient dermatology clinic in Singapore. Methods This case study highlights the clinical history, signs and symptoms, pathophysiology, nursing management, and patient education of a child with EBS-DM. Conclusion The management of EBS-DM poses challenges in the absence of a definite cure. Patients with EBS-DM need individualized care, according to the severity of their disease. A multidisciplinary team approach of providing holistic care helps to maximize the health, outcome, and quality of life for these patients.

Whole-transcriptome gene expression profiling in an epidermolysis bullosa simplex Dowling-Meara model keratinocyte cell line uncovered novel, potential therapeutic targets and affected pathways.

BackgroundTo be able to develop effective therapeutics for epidermolysis bullosa simplex (EBS), it is necessary to elucidate the molecular pathomechanisms that give rise to the disease’s characteristic severe skin-blistering phenotype.ResultsStarting with a whole-transcriptome microarray analysis of an EBS Dowling-Meara model cell line (KEB7), we identified 207 genes showing differential expression relative to control keratinocytes. A complementary qRT-PCR study of 156 candidates confirmed 76.58 % of the selected genes to be significantly up-regulated or down-regulated (p-value <0.05) within biological replicates. Our hit list contains previously identified genes involved in epithelial cell proliferation, cell-substrate adhesion, and responses to diverse biological stimuli. In addition, we identified novel candidate genes and potential affected pathways not previously considered as relevant to EBS pathology.ConclusionsOur results broaden our understanding of the molecular processes dysregulated in EBS.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1783-7) contains supplementary material, which is available to authorized users.

In silico analysis of all point mutations on the 2B domain of K5/K14 causing epidermolysis bullosa simplex: a genotype-phenotype correlation.

Epidermolysis bullosa simplex (EBS) is a genodermatosis caused by mutations in keratins 5 and 14 (K5 and K14), which leads to fragility of basal keratinocytes and eventually epidermal cytolysis and blistering. Depending upon the severity of symptoms, EBS is classified into three major subtypes. In order of increasing severity these classes are EBS, localized (EBS-loc), EBS, other generalized (EBS, gen-nonDM), and EBS, Dowling-Meara (EBS-DM). We have searched and assembled 36 previously reported point mutations located on the 2B domain of K5/K14 in order to investigate the effects of point mutations. By performing a comprehensive in silico analysis we determine the underlying relationship between the mutation and its phenotypic effects. Our result showed that all pathogenic point mutations exert their dominant negative effect on the K5/K14 coiled-coil heterodimer complex by altering interchain interaction, leading to the changes in stability and assembly competence of the heterodimer complex. The physico-chemical properties of substituted amino acid and location of the mutation are also deeply correlated with disease severity. In addition, we found a SNP previously reported as non-pathogenic (K14 p.M338R) that likely affects the stability of the dimer structure due to the loss of interchain interaction and steric clashes. Overall, our finding demonstrates the significance of in silico characterization of EBS severity and would allow for accurate genetic counseling and prenatal diagnosis.

Imbalance of intermediate filament component keratin 14 contributes to increased stress signalling in epidermolysis bullosa simplex

An important characteristic of epidermolysis bullosa simplex Dowling-Meara (EBS-DM) keratinocytes is the increased level of Jun N-terminal kinase (JNK) stress signalling, which is thought to contribute to the disease phenotype. In this work, we report on the dramatic up-regulation of cytokeratin 14 (K14) in the EBS-DM model cell line KEB7 at both the transcriptional and translational levels, which is noteworthy because KEB7 patient cells are heterozygous for a missense mutation (R125P) in K14. By performing functional assays, we show a direct link between overexpressed wild-type K14 and increased JNK signalling in healthy, immortalized keratinocytes. This observation led us to hypothesize a positive feedback model in which mutant (R125P) K14 triggers JNK signalling, leading to increased AP1-dependent expression of K14, which in turn amplifies JNK signalling further. We therefore suggest that an imbalance of cytoplasmic K14 monomers and K14 incorporated into the intermediate filament (IF) network leads to elevated stress signalling, potentially altering IF dynamics by phosphorylation, which as a side effect, weakens EBS-DM keratinocytes.

Verrucous carcinoma in epidermolysis bullosa simplex is possibly associated with a novel mutation in the keratin 5 gene

Epidermolysis bullosa simplex (EBS) is mainly caused by mutations in the KRT5 and KRT14 genes. Squamous cell carcinoma (SCC) represents the second most frequent skin neoplasia with complex aetiology. The molecular events disrupting the orchestrated interplay between the cytoskeleton, cell adhesion molecules and signalling proteins are ill understood in SCC. We describe the molecular background and the unusual course of the disease in a patient with EBS Dowling-Meara, severe keratoderma and a massive verrucous carcinoma. Skin and tumour samples from the patient were analysed using light microscopy, immunohistochemistry and immunofluorescence mapping. Mutation analysis of the KRT5 and KRT14 genes identified the novel KRT5 mutation p.E477D. Invasive tumour areas were characterized by downregulation of keratins 5 and 14, reduced and irregular desmocollin-2 expression and increased expression of keratins 6, 16 and 17. Levels of Ki-67 were increased and levels of E-cadherin strongly reduced in the tumour tissue. In this case a novel KRT5 mutation led to increased fragility of keratinocytes. Desmosome and adherens junctions were destabilized, which may trigger keratinocyte-mediated inflammation, possibly via p120-catenin-dependent signalling, suggesting a link between a keratin mutation and SCC, which adds weight to the hypothesis that disturbance of the cytoskeleton represents a major cause in the appearance of the malignant phenotype. Some individuals with EBS may be at risk of developing secondary SCC.

Gene expression analysis of an epidermolysis bullosa simplex Dowling‐Meara cell line by subtractive hybridization: recapitulation of cellular differentiation, migration and wound healing

An intact keratin 5/keratin 14 intermediate filament cytoskeleton is vital for the integrity of basal keratinocytes and for the development and maintenance of epidermal structures. In patients with epidermolysis bullosa simplex Dowling-Meara (EBS-DM), heterozygous mutations in the keratin 14 gene in keratinocytes cause a cytoskeletal collapse leading to fragile cells susceptible to cellular stress. The primary aim of this work was to extend analysis of differentially expressed genes in an EBS-DM model cell line to obtain insights into the molecular consequences resulting from the keratin 14 mutation. In a first step, suppression subtractive hybridization (SSH), a powerful technology to enrich for differentially expressed genes, was used to identify genes whose up-regulation may be a direct or indirect result of the keratin 14 mutation, R125P. We discovered 55 candidate genes (SSH genes) that were further analysed by RTq-PCR. Of the 55 SSH genes, 14 (25.45%) were found to be congruently up-regulated. Bioinformatic analysis revealed significant enrichment of genes regulating epidermal development, migration, apoptosis and wound healing.

A Large Mutational Study in Pachyonychia Congenita

Pachyonychia congenita (PC) is a rare autosomal dominant skin disorder characterized predominantly by nail dystrophy and painful palmoplantar keratoderma. Additional clinical features include oral leukokeratosis, follicular keratosis, and cysts (steatocysts and pilosebaceous cysts). PC is due to heterozygous mutations in one of four keratin genes, namely, KRT6A, KRT6B, KRT16, or KRT17. Here, we report genetic analysis of 90 new families with PC in which we identified mutations in KRT6A, KRT6B, KRT16, or KRT17, thereby confirming their clinical diagnosis. A total of 21 previously unreported and 22 known mutations were found. Approximately half of the kindreds had mutations in KRT6A (52%), 28% had mutations in KRT16, 17% in KRT17, and 3% of families had mutations in KRT6B. Most of the mutations were heterozygous missense or small in-frame insertion/deletion mutations occurring within one of the helix boundary motif regions of the keratin polypeptide. More unusual mutations included heterozygous splice site mutations, nonsense mutations, and a 1-bp insertion mutation, leading to a frameshift and premature termination codon. This study, together with previously reported mutations, identifies mutation hotspot codons that may be useful in the development of personalized medicine for PC.

Mutations in KRT5 and KRT14 cause epidermolysis bullosa simplex in 75% of the patients

Epidermolysis bullosa simplex (EBS) is a mechanobullous genodermatosis that may be caused by mutations in the genes KRT5 and KRT14 encoding the basal epidermal keratins 5 (K5) and 14 (K14). Three main clinical subtypes of EBS exist, differing in onset, distribution and severity of skin blistering. Previous reports of KRT5 and KRT14 mutations suggest a correlation between the location of the mutation and the severity of the associated EBS phenotype. The prevalence of KRT5/KRT14 mutations and the genotype-phenotype correlation in the largest tissue-confirmed EBS population is investigated. KRT5 and KRT14 genomic DNA and cDNA sequences of 76 clinically well-defined unrelated EBS probands were amplified and then subjected to direct sequencing and product length analysis. Immunofluorescence microscopy on patients' skin biopsies with antibodies against K5 and K14 was performed to study protein expression. In 57 of 76 (75%) probands 41 different KRT5 and KRT14 mutations were identified, of which 12 were novel. Mutations affecting the highly conserved helix boundary motifs of the rod domains of K5 and K14, and the K14 helix initiation motif in particular, were associated with the severest, EBS Dowling-Meara, phenotype. In 21 EBS probands (37%) the mutation was de novo. In 19 probands (25%) KRT5 or KRT14 mutations were excluded. The phenotype-genotype correlation observed in this large EBS population underscores the importance of helix boundary motifs for keratin assembly. Only three-quarters of biopsy-confirmed EBS probands have KRT5 or KRT14 mutations, indicating genetic heterogeneity in EBS. Alternative gene candidates are discussed.

Epidermolysis Bullosa Simplex Dowling-Meara - A case report

A case with Epidermolysis bullosa simplex DowlingMeara is presented. It concerns a 20 days breast-fed girl with severe blistering and erosions on the skin formed at birth after minor mechanical trauma. There are no other affected relatives. A medical examination showed normal somatic and visceral status. There were multiple herpetiform grouped bullous and erosive lesions on the face, trunk, upper and lower limbs, palms and soles. The mucous membranes were not affected. There was also a marked nail dystrophy on the fingers and toenails. The electron microscopic examination revealed cytolysis of the basal keratinocytes with clumping of the perinuclear tonofilaments in the lesional skin. Because of the clinical features and the results of the electron microscopic examination of the skin the case here reported should be considered as an Epidermolysis bullosa simplex DowlingMeara. The child is followed up to the age of three. The course of the disease was benign with a decreased formation of blisters and erosions. The marked nail dystrophy was persistent. There was palmar and plantar hyperkeratosis. The child’s growth, neural and psychic development was normal. The early diagnosis of the bullous epidermolysis is helpful in the prognostic assessment of the disease and in the medical and genetic advice for the parents.

Mutation screening of entire keratin 5 and keratin 14 genes and identification of a novel mutation in a Chinese family with epidermolysis bullosa simplex Dowling‐Meara

Journal of the European Academy of Dermatology and VenereologyVolume 22, Issue 12 p. 1510-1512 Mutation screening of entire keratin 5 and keratin 14 genes and identification of a novel mutation in a Chinese family with epidermolysis bullosa simplex Dowling-Meara H Yuan, H Yuan Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China, Equal contribution. Search for more papers by this authorF Liu, F Liu Department of Dermatology, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, 100020, China, Equal contribution. Search for more papers by this authorB Xiao, Corresponding Author B Xiao Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China, *Corresponding author, tel. +86 10 85231624; fax +86 10 65064135; E-mail: xiaobai_1954@yahoo.com.cnSearch for more papers by this authorY He, Y He Department of Dermatology, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, 100020, China,Search for more papers by this authorY Liang, Y Liang Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China,Search for more papers by this authorJ Liu, J Liu Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China,Search for more papers by this author H Yuan, H Yuan Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China, Equal contribution. Search for more papers by this authorF Liu, F Liu Department of Dermatology, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, 100020, China, Equal contribution. Search for more papers by this authorB Xiao, Corresponding Author B Xiao Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China, *Corresponding author, tel. +86 10 85231624; fax +86 10 65064135; E-mail: xiaobai_1954@yahoo.com.cnSearch for more papers by this authorY He, Y He Department of Dermatology, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, 100020, China,Search for more papers by this authorY Liang, Y Liang Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China,Search for more papers by this authorJ Liu, J Liu Basic Medical Research Center, Beijing Chao Yang Hospital affiliate of Capital University of Medical Science, Beijing, China,Search for more papers by this author First published: 24 November 2008 https://doi.org/10.1111/j.1468-3083.2008.02687.xCitations: 5 DOI: 10.1111/j.1468-3083.2008.02687.x Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume22, Issue12December 2008Pages 1510-1512 RelatedInformation

Epidermolysis Bullosa Simplex in Scotland Caused by a Spectrum of Keratin Mutations

Epidermolysis bullosa simplex (EBS) is an inherited skin disorder caused by mutations in keratins K5 (keratin 5) and K14 (keratin 14), with fragility of basal keratinocytes leading to epidermal cytolysis and blistering. Patients present with widely varying severity and are classified in three main subtypes: EBS Weber-Cockayne (EBS-WC), EBS Köbner (EBS-K), and EBS Dowling-Meara (EBS-DM), based on distribution and pattern of blisters. We could identify K5/K14 mutations in 20 out of the 43 families registered as affected by dominant EBS in Scotland; with previous studies this covers 70% of all Scottish EBS patients, making this the most comprehensively analyzed EBS population. Nine mutations are novel. All mutations lie within five previously identified rod domain hotspots and the severest blistering was associated with mutations in the helix boundary motifs. In some cases, the same mutation caused symptoms of EBS-WC and/or EBS-K, both within and between families, suggesting a contribution of additional factors to the phenotype. In some patients, no mutations were found in K5, K14, or K15, suggesting involvement of other genes. The results confirm that EBS is best considered as a single disorder with a spectrum of phenotypic variations, from severe EBS-DM at one extreme to mild EBS-WC at the other.

Three Severe Cases of EBS Dowling-Meara Caused by Missense and Frameshift Mutations in the Keratin 14 Gene

We report three unrelated patients affected at birth with an unusually severe form of epidermolysis bullosa simplex Dowling-Meara type (EBS-DM) because of mutations in KRT14 encoding keratin 14. Two patients were heterozygous for the previously described p.M119T mutation. The third patient was heterozygous for a novel c.1246delC mutation predicting the replacement of the helix termination peptide and the tail domain by a 25 amino-acid aberrant carboxyterminal sequence. At age 2 years, patients carrying the p.M119T mutation still suffered from severe EBS-DM, whereas the patient harboring the c.1246delC mutation has improved over time. These cases illustrate genotype-phenotype correlations and have implications for genetic counselling of EBS.

Functional testing of keratin 14 mutant proteins associated with the three major subtypes of epidermolysis bullosa simplex.

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominantly inherited skin disorders characterized by the development of intra-epidermal skin blisters on mild mechanical trauma. The three major clinical subtypes (Weber-Cockayne, Koebner and Dowling-Meara) are all caused by mutations in either the keratin 5 (KRT5) or keratin 14 (KRT14) gene. Previously, we identified three novel KRT14 missense mutations in Danish EBS patients associated with the three different forms of EBS (1). The identified KRT14 mutations represent the full spectrum of the classical EBS subtypes. In the present study we investigated these mutations in a cellular expression system in order to analyse their effects on the keratin cytoskeleton. KRT14 expression vectors were constructed by fusing the nucleotide sequence encoding the FLAG reporter peptide to the 3' end of the KRT14 cDNA sequences. The expression vectors were transiently transfected into normal human primary keratinocytes (NHK), HaCaT or HeLa cells in order to analyze the ability of the mutant K14 proteins to integrate into the existing endogenous keratin filament network (KFN). No effect on the keratin cytoskeleton was observed upon transfection of NHK with the various K14 constructs neither with nor without a subsequently induced heat-stress. In contrast, all constructs, including wild-type K14, caused collapse of the endogenous KFN in a small fraction of the transfected HeLa and HaCaT cells. However, overexpression of the mutation associated with the most severe form of the disease, EBS Dowling-Meara, resulted in a higher number of transfected HaCaT cells with KFN collapse (P < 0.001). Thus, although a background KFN perturbance was observed upon transfection with the wild-type K14 construct, the mutant protein associated with the most severe form of EBS worsened the KFN perturbation significantly compared with the mutant proteins associated with the milder forms of the disease and the normal K14 protein. This shows that the clinical severity of disease-associated mutations identified in patients can be tested using this expression system, although it can not at present be used to discriminate between the milder forms. Assessment of the endogenous K14 protein expression in NHK and HaCaT cells indicated that the higher level of endogenous keratin expression in NHK might make these cells more resistant to perturbation of the keratin cytoskeleton by overexpressed K14 protein than HaCaT cells.

A Novel Mutation in the Helix Termination Peptide of Keratin 5 Causing Epidermolysis Bullosa Simplex Dowling–Meara

Epidermolysis bullosa simplex Dowling-Meara (MIM# 1317600) is the most severe of the three common epidermolysis bullosa simplex subtypes. In addition to the palmoplantar distribution seen in other epidermolysis bullosa simplex subtypes, extensive herpetiform blistering spontaneously develops on the trunk and limbs and may lead to scarring or milia formation. The keratin 5 and keratin 14 genes encode proteins that form the primary structural components of the basal epidermal keratinocytes, mutations in either of these genes can cause epidermolysis bullosa simplex. In this study we sequenced these genes in a family with epidermolysis bullosa simplex Dowling-Meara. We report a novel T to C transition in the helix termination peptide of K5 that causes a nonconservative substitution of a highly conserved amino acid within this critical region (I466T). This mutation adds to those previously reported and provides further evidence of phenotype-genotype correlation in epidermolysis bullosa simplex.

Is Cyproheptadine Effective in the Treatment of Subjects With Epidermolysis Bullosa Simplex-Dowling-Meara?

Epidermolysis bullosa simplex—Dowling-Meara (EBS-DM) is a severe form of EBS, with oral and nail involvement as well as severe skin blistering. Reports1,2of treatment with 5-hydroxytryptamine—2 antagonists reducing the severity of blisters in subjects with EBS-DM prompted us to study cyproheptadine hydrochloride therapy in 13 individuals with a diagnosis of EBS-DM confirmed by electron microscopic examination. Participants served as their own controls. There was a 2-week observational period, an initial 6-week period during which cyproheptadine was taken daily, a 4-week period with no treatment, and a second 6-week regimen of daily administration of cyproheptadine. Standard dosages of cyproheptadine were used.3The study was designed in this manner in an attempt to compensate for temporal variation in blister formation as well as variations in season, weather, and activity levels of the participants. Subjects were asked to record the number of blisters lanced each day rather than the

A keratin K14 gene mutation in a Japanese patient with the Dowling-Meara type of epidermolysis bullosa simplex

Epidermolysis bullosa simplex (EBS) is caused by an aberration of the keratin intermediate filaments and recent studies indicated causal mutations in the keratin K14 and K5 genes. In this study, we examined keratin K14/5 gene mutation in a Japanese patient with EBS Dowling-Meara (EBSDM). The patient had a C to T transition at the first position of codon 125, which resulted in Arg → Cys at the N-terminus of the rod domain in the keratin K14 gene. The mutation position described here was identical to those reported in some other EBSDM patients. Our result revealed mutation in the peptide initiating helical structure of keratin K14 and, together with the results of other workers, suggests that the mutation in the keratin K14 gene of EBSDM sufferers occurs in virtually every ethnic group and geographical area.