Epidermolysis Bullosa Simplex Research Articles

KRT5 in-frame deletion in a family of German Shepherd dogs with split paw pad disease resembling localized epidermolysis bullosa simplex in human patients.

Split paw pad disease is a scarcely defined phenotype characterized by skin lesions on the paw pads of dogs. We studied a family of German Shepherd dogs, in which four dogs developed intermittent paw pad lesions and lameness. The paw pads of two of the affected dogs were biopsied and demonstrated cleft formation in the stratum spinosum and stratum corneum, the outermost layers of the epidermis. Whole genome sequencing data from an affected dog revealed a private heterozygous 18 bp in frame deletion in the KRT5 gene. The deletion NM_001346035.1:c.988_1005del or NP_001332964.1:p.(Asn330_Asp335del) is predicted to lead to a loss of six amino acids in the L12 linker domain of the encoded keratin 5. KRT5 variants in human patients lead to various subtypes of epidermolysis bullosa simplex (EBS). Localized EBS is the mildest of the KRT5-related human diseases and may be caused by variants affecting the L12 linker domain of keratin 5. We therefore think that the detected KRT5 deletion in dogs represents a candidate causal variant for the observed skin lesions in dogs. However, while the clinical phenotype of KRT5-mutant dogs of this study closely resembles human patients with localized EBS, there are differences in the histopathology. EBS is defined by cleft formation within the basal layer of the epidermis while the cleft formation in the dogs described herein occurred in the outermost layers, a hallmark of split paw pad disease. Our study provides a basis for further studies into the exact relation of split paw pad disease and EBS.

Epidermolysis Bullosa in an Infant Heterozygous for Mutation in LAMC2 Gene: A Case Report

Epidermolysis bullosa is a heterogenous skin disease caused by genes associated with skin integrity and dermal–epidermal adhesion. The four main categories include: epidermolysis bullosa simplex, junctional epidermolysis bullosa, dystrophic epidermolysis bullosa, and kindler syndrome. We report the case of a one-month-old infant who was brought to the emergency department due to complaint of fever and a bullous exanthem. Skin cultures were positive for methicillin-sensitive Staphylococcus aureus and Escherichia coli. Whole exome sequencing revealed mutations in LAMC2 gene. Junctional epidermolysis bullosa is associated with poor prognosis. Healthcare professionals and parents should be educated in a specific way as patients with this condition are in need of special care.

Descriptive Study of the Clinical and Molecular Features of Epidermolysis Bullosa Patients in a Romanian European Reference Network-Skin Affiliated Reference Center.

During the last 10 years, in Romania, progress has been made for the welfare of patients suffering from epidermolysis bullosa (EB). In five university hospitals, affiliated with the National Program for the Treatment of Rare Diseases, highly trained specialists diagnose and treat patients with this rare condition. Regarding diagnosis, limitations still exist as immunofluorescence mapping and molecular genetic analysis are not accessible, and generally not reimbursed. Our objective is to present the experience in diagnosing EB patients at Colentina Clinical Hospital, highlighting genotype-phenotype correlations observed in our cohort of patients. The records of the patients enrolled between 2012 and 2024 were analyzed considering clinical aspects, and, when available, immunofluorescence mapping, transmission electron microscopy, and genetic molecular analysis. Fifty-six patients were identified, of whom 31 cases were of dystrophic EB, threewere of junctional EB, and 11 were of simplex EB. For 11 cases, the EB type could not be determined. Regarding EB simplex, two patients with KRT5 mutations and three patients with KRT14 mutations with various clinical expressions, from mild phenotype to severe forms, were identified. Three severe junctional EB patients were registered in our database and for one of the patients, two previously unreported mutations in the LAMA3 gene were identified. Regarding dystrophic EB, 31 cases were identified, of which 25 were recessive dystrophic casesand six were dominant dystrophic cases. Molecular genetic testing was performed for 15 patients, and the most common variant was c.425A>G, identified in six cases. Two previously unreported mutations were identified, namely,COL7A1 c.5416G>C, a heterozygous missense variant in a patient with a mild phenotype, mainly with nail involvement, and COL7A1 c.5960del, a variant that generates a frameshift in exon 72 resulting in a premature stop codon; this variant was identified in two siblings with a severe recessive dystrophic. Important steps have been made in identifying the correct and complete diagnosis, as well as the characterization of EB patients addressing our reference center. The findings underscore the pivotal role of molecular genetic testing in confirming diagnoses and elucidating inheritance patterns, especially in cases with atypical presentations or de novo mutations.

Epidermolysis Bullosa: Two rare case reports of COL7A1 and EBS-GEN SEV KRT14 variants with review of literature

EpidermolysisBullosa is a rare hereditary skin condition that causes blisters. Genes encoding structural proteins at or near the dermal-epidermal junction are mutated recessively or dominantly, and this is the primary cause of EB. Herein, two Chinese boys were diagnosed with the condition, each with a different variant in a gene that serves as a reference for EB genetic counseling. Skincare significantly impacted their prognosis and quality of life.Case presentationTwo Chinese boys, with phenotypically normal parents, have been diagnosed with distinct blister symptoms, one with Dominant Dystrophic Epidermolysis Bullosa and the other with a severe form of Epidermolysis Bullosa Simplex. The first patient had a G-to-A variant in the COL7A1 allele, at nucleotide position 6163 which was named “G2055A”. The proband is heterozygous for Dystrophic Epidermolysis Bullosa due to a COL7A1 allele with a glycine substitution at the triple helix domain. A similar variant has been discovered in his mother, indicating its potential transmission to future generations. Another patient had severe Epidermolysis Bullosa Simplex with a rare c.377T > A variant resulting in substitution of amino acid p.Leu126Arg (NM_000526.5 (c.377T > G, p.Leu126Arg) in the Keratin 14 gene. In prior literature, Keratin 14 has been associated with an excellent prognosis. However, our patient with this infrequent variant tragically died from sepsis at 21 days old. There has been a reported occurrence of the variant only once.ConclusionOur study reveals that Epidermolysis Bullosa patients with COL7A1 c.6163G > A and KRT14 c.377T>A variants have different clinical presentations, with dominant forms of Dystrophic EB having milder phenotypes than recessive ones. Thus, the better prognosis in the c.6163G > A patient. Furthermore, c.377T>A patient was more prone to infection than the patient with c.6163G>A gene variant. Genetic testing is crucial for identifying the specific variant responsible and improving treatment options.

Two-days Old Newborn with Epidermolysis Bullosa Simplex: Severe Subtype

This case report details a rare instance of severe epidermolysis bullosa simplex (EBS) in a two-day-old neonate with distinctive clinical features. The patient exhibited extensive blistering on the hands, tongue, face, and ears, prompting admission to the Neonatal Intensive Care Unit. Ge-netic testing confirmed a heterozygous dominant negative mutation on the KRT14 gene, confirming the diagnosis of severe EBS. Laboratory findings revealed leukocytosis and electrolyte abnormalities, while biopsy examination showcased subepidermal blisters. The neonate received supportive management, including nasogastric tube feeding and wound care, resulting in improvement and subsequent discharge with a follow-up plan. Discussion delves into EB classification, emphasizing the unique features of severe EBS. A succinct comparison table outlines clinical distinctions among localized, intermediate, severe, and mottled pigmentation EBS. This case highlights the complexities in diagnosing and managing severe EBS in neonates and advocates for further research to establish comprehensive treatment guidelines, especially in newborns, and explore emerging therapies for epidermolysis bullosa.

Exploring the Impact of Epidermolysis Bullosa on Parents and Caregivers: A Cross-Cultural Validation of the Epidermolysis Bullosa Burden of Disease Questionnaire.

Epidermolysis bullosa (EB) is a heterogeneous group of genetically inherited skin and mucosal fragility disorders. EB may have a profound impact on parental physical and psychosocial health. This study was designed to evaluate the disease burden in parents of patients with EB and identify out-of-pocket (OOP) expenditures for EB care in Saudi Arabia. Thirty-eight caregivers of patients with EB were recruited from the Saudi EB registry to participate. All participants completed the EB Burden of Disease (EB-BoD) questionnaire. Data were collected between May 2020 and December 2020. The sample included 10 patients with EB simplex (EBS), 10 with junctional EB (JEB), 14 with dystrophic EB (DEB), and 4 with an unknown type. Mothers were the primary caregivers in 89.5% of cases. The mean EB-BoD score was 53 ± 21.5. The family-life and child's life dimensions had the higher burden. The mean EB-BoD score observed in patients with DEB was 62.4±16.8 versus 45.7 ± 19.42 for EBS. The EB-BoD score was correlated with the patient's family income. Most caregivers (97.4%) reported OOP expenditure, with a mean monthly OOP expenditure of $575.5± $701.1. OOP expenses increased with the severity of the condition. This study highlights the need for support services for parents caring for patients with EB.

Gross motor development in children with epidermolysis bullosa.

Epidermolysis bullosa (EB) is a group of rare, congenital skin disorders, characterized by skin fragility and formation of blisters. The gross motor outcomes of children with EB are not known. The primary objective of the study was to measure the proportion of gross motor delay in children with EB. The secondary objectives were to measure the difference in gross motor outcomes between EB sub-types and change in gross motor outcomes over time. Children with EB, aged between one month and five and a half years of age, attending the Sydney Children's Hospital, Epidermolysis Bullosa Clinic, were eligible. Carers completed Ages and Stages Questionnaires, Third Edition, on behalf of their children. Questionnaires were scored, and outcomes were compared to age-expected norms. There were 24 participants to complete a questionnaire. Eleven participants completed additional questionnaires over the 24 month study duration. The proportion of children with EB with gross motor delay was greater than age-expected norms (29.17% vs. 2.5%). The delay occurred in children with recessive dystrophic (80%) and epidermolysis bullosa simplex (33.33%) sub-types, but not dominant dystrophic (0%). No children with Junctional EB or Kindler EB joined this study. This study demonstrates a difference in gross motor outcomes in children with EB. Children with recessive dystrophic and epidermolysis bullosa simplex should be prioritized for monitoring of, and intervention for, gross motor outcomes through multidisciplinary care. Further research investigating long-term outcomes for children with EB and the effectiveness of interventions would be beneficial.

Allele-specific CRISPR-Cas9 editing of dominant epidermolysis bullosa simplex in human epidermal stem cells

Epidermolysis Bullosa Simplex (EBS) is a rare skin disease inherited mostly in an autosomal dominant manner. Patients display a skin fragility that leads to blisters and erosions caused by minor mechanical trauma. EBS phenotypic and genotypic variants are caused by genetic defects in intracellular proteins whose function is to provide the attachment of basal keratinocytes to the basement membrane zone and most of EBS cases display mutations in keratin 5 (KRT5) and keratin 14 (KRT14) genes. Besides palliative treatments, there is still no long-lasting effective cure to correct the mutant gene and abolish dominant negative effect of the pathogenic protein over its wild-type counterpart. Here, we propose a molecular strategy for EBS01 patient’s keratinocytes carrying a monoallelic c.475/495del21 mutation in KRT14 exon1. Through the CRISPR/Cas9 system we performed a specific cleavage only on the mutant allele and restore a normal cellular phenotype and a correct intermediate filament network, without affecting the epidermal stem cell, referred to as holoclones, which play a crucial role in epidermal regeneration.

Inheritance of the Epidermolysis Bullosa Subtypes

Epidermolysis bullosa (EB) is a group of inherited disorders that cause skin to blister and tear easily. The disease is caused by mutations in structural proteins that are key for maintaining the integrity of the skin’s basement membrane zone or dermoepidermal junction. EB can be inherited in two ways: autosomal dominant and autosomal recessive. The most common form of EB, epidermolysis bullosa simplex (EBS), as well as some forms of dystrophic epidermolysis bullosa (DEB) are inherited in an autosomal dominant pattern. This means they are passed down from an affected parent to half of his or her children. Other forms of EB, such as junctional epidermolysis bullosa (JEB) and some forms of DEB, are inherited in an autosomal recessive pattern. This means that two copies of the mutated gene, one from each parent, are required to develop the condition.

Hypermobility in patients with epidermolysis bullosa—A retrospective observational study from a national referral center

AbstractBackgroundEpidermolysis bullosa (EB) is an inherited genodermatosis of variable severity characterised by skin and mucosal fragility commonly associated with altered gait patterns and hypermobility.ObjectivesTo define the altered gait pattern and identify possible causes in patients with EB.MethodsRetrospective review of the EB database to identify children with EB with at least one physiotherapy assessment between 2009 and 2022.ResultsForty‐eight children out of 59 referrals to physiotherapy with an altered gait pattern were identified (81.3%); 23 (48%) had recessive dystrophic EB (RDEB), 17 (36%) EB simplex, five (10%) Junctional EB (JEB) and three (6%) dominant dystrophic EB (DDEB). The patho‐mechanical altered gait patterns were characterised by altered load‐bearing surface in contact with the floor (63%), short shuffling pattern with high cadence and decreased single support (42%) and equinovarus (toe walking) (6%). Hypermobility (as defined by the Beighton score) was present in 67% of patients: 43% in RDEB, 88% in EBS, 100% in JEB and 67% in DDEB.ConclusionsIn this study, we provide the first accurate data for the causes of altered gait patterns in children with EB. Healthcare professionals should be aware of joint hypermobility and its effect on gait in this patient cohort.

Dystonin modifiers of junctional epidermolysis bullosa and models of epidermolysis bullosa simplex without dystonia musculorum.

The Lamc2jeb junctional epidermolysis bullosa (EB) mouse model has been used to demonstrate that significant genetic modification of EB symptoms is possible, identifying as modifiers Col17a1 and six other quantitative trait loci, several with strong candidate genes including dystonin (Dst/Bpag1). Here, CRISPR/Cas9 was used to alter exon 23 in mouse skin specific isoform Dst-e (Ensembl GRCm38 transcript name Dst-213, transcript ID ENSMUST00000183302.5, protein size 2639AA) and validate a proposed arginine/glutamine difference at amino acid p1226 in B6 versus 129 mice as a modifier of EB. Frame shift deletions (FSD) in mouse Dst-e exon 23 (Dst-eFSD/FSD) were also identified that cause mice carrying wild-type Lamc2 to develop a phenotype similar to human EB simplex without dystonia musculorum. When combined, Dst-eFSD/FSD modifies Lamc2jeb/jeb (FSD+jeb) induced disease in unexpected ways implicating an altered balance between DST-e (BPAG1e) and a rarely reported rodless DST-eS (BPAG1eS) in epithelium as a possible mechanism. Further, FSD+jeb mice with pinnae removed are found to provide a test bed for studying internal epithelium EB disease and treatment without severe skin disease as a limiting factor while also revealing and accelerating significant nasopharynx symptoms present but not previously noted in Lamc2jeb/jeb mice.

Clinical and molecular features in a cohort of Middle Eastern patients with epidermolysis bullosa.

Epidermolysis bullosa (EB) features skin and mucosal fragility due to pathogenic variants in genes encoding components of the cutaneous basement membrane. Based on the level of separation within the dermal-epidermal junction, EB is sub-classified into four major types including EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB), and Kindler EB (KEB) with 16 EB-associated genes reported to date. We ascertained a cohort of 151 EB patients of various Middle Eastern ethnic backgrounds. The cohort was comprised of EBS (64%, 97/151), DEB (21%, 31/151), JEB (12%, 18/151), and KEB (3%, 5/151). KRT14 and KRT5 variants were most common among EBS patients with 43% (42/97) and 46% (45/97) of EBS patients carrying mutations in either of these two genes, respectively. Truncal involvement was more common in KRT14-associated EBS as compared to EBS due to KRT5 mutations (p < .05). Mutations in COL17A1 and laminin 332-encoding genes were identified in 55% (10/18) and 45% (8/18) of JEB patients. Scarring alopecia, caries, and EB nevi were most common among JEB patients carrying COL17A1 mutations as compared to laminin 332-associated JEB (p < .05). Abnormal nails were evident in most DEB and JEB patients while poikiloderma was exclusively observed in KEB (p < .001). EB patients of Middle Eastern origin were found to feature specific phenotype-genotype correlations of relevance to the diagnosis and genetic counseling of patients in this region.

Plectin Deficiency in Fibroblasts Deranges Intermediate Filament and Organelle Morphology, Migration, and Adhesion

Plectin, a highly versatile and multifunctional cytolinker, has been implicated in several multisystemic disorders. Most sequence variations in the human plectin gene (PLEC) cause epidermolysis bullosa simplex with muscular dystrophy (EBS-MD), an autosomal recessive skin-blistering disorder associated with progressive muscle weakness. In this study, we performed a comprehensive cell biological analysis of dermal fibroblasts from three different patients with EBS-MD, where PLEC expression analyses revealed preserved mRNA levels in all cases, whereas full-length plectin protein content was significantly reduced or completely absent. Downstream effects of pathogenic PLEC sequence alterations included massive bundling of vimentin intermediate filament networks, including the occurrence of ring-like nuclei-encasing filament bundles, elongated mitochondrial networks, and abnormal nuclear morphologies. We found that essential fibroblast functions such as wound healing, migration, or orientation upon cyclic stretch were significantly impaired in the cells of patients with EBS-MD. Finally, EBS-MD fibroblasts displayed reduced adhesion capacities, which could be attributed to smaller focal adhesion contacts. Our study not only emphasizes plectin's functional role in human skin fibroblasts, it also provides further insights into the understanding of EBS-MD-associated disease mechanisms.

Epidermolysis bullosa: a tale of two sisters

Epidermolysis bullosa (EB) is a clinically and genetically heterogenous, inherited, mechanobullous disorder characterised by spontaneous or trauma induced blisters over skin and mucous membranes. Four major forms are: EB Simplex, EB Junctional, EB dystrophic and mixed. A 11-year-old and a 9 year old female child, both sisters, accompanied by their father, presented to dermatology OPD, with chief complaints of multiple raw areas over elbows and knees since infancy. There was history of fluid filled lesions which were induced by trauma or friction during handling or while playing. These lesions ruptured on their own or on trauma to form raw areas with crusting which further healed with scarring and small white raised lesions. Also, he gave history of loss of nails following blistering on toes in infancy. No associated systemic complaints were noted. On examination, both of them presented with multiple erosions and ulcers with oozing of blood, few bullae and crusted lesions over elbows, knees and feet. There were multiple atrophic scars and skin coloured to whitish papules [milia] over feet, ankles, elbows and knees. There were loss of nails of toes of both feet. On biopsy, histopathological examination revealed bullae at dermoepidermal junction. Diagnosis of EB junctional was made. EB is a rare inherited disorder. Its management includes prevention and healing of blisters and infection. Psychological support to patients and their families is of prime importance.

Roles of dystonin isoforms in the maintenance of neural, muscle, and cutaneous tissues.

Dystonin (DST), also known as bullous pemphigoid antigen 1 (BPAG1), encodes cytoskeletal linker proteins belonging to the plakin family. The DST gene produces several isoforms, including DST-a, DST-b, and DST-e, which are expressed in neural, muscle, and cutaneous tissues, respectively. Pathogenic DST mutations cause hereditary sensory and autonomic neuropathy type 6 (HSAN-VI) and epidermolysis bullosa simplex (EBS); therefore, it is important to elucidate the roles of DST isoforms in multiple organs. Recently, we have used several Dst mutant mouse strains, in which the expression of Dst isoforms is disrupted in distinct patterns, to gain new insight into how DST functions in multiple tissues. This review provides an overview of the roles played by tissue-specific DST isoforms in neural, muscle, and cutaneous tissues.

LB1724 Autosomal recessive epidermolysis bullosa simplex caused by missense and inframe mutations in PLEC is associated with minimal or delayed muscular dystrophy and possibly less laboratory abnormalities: A series of nine cases

LB1724 Autosomal recessive epidermolysis bullosa simplex caused by missense and inframe mutations in PLEC is associated with minimal or delayed muscular dystrophy and possibly less laboratory abnormalities: A series of nine cases

How to analyze continuous and discrete repeated measures in small-sample cross-over trials?

To optimize the use of data from a small number of subjects in rare disease trials, an at first sight advantageous design is the repeated measures cross-over design. However, it is unclear how these within-treatment period and within-subject clustered data are best analyzed in small-sample trials. In a real-data simulation study based upon a recent epidermolysis bullosa simplex trial using this design, we compare non-parametric marginal models, generalized pairwise comparison models, GEE-type models and parametric model averaging for both repeated binary and count data. The recommendation of which methodology to use in rare disease trials with a repeated measures cross-over design depends on the type of outcome and the number of time points the treatment has an effect on. The non-parametric marginal model testing the treatment-time-interaction effect is suitable for detecting between group differences in the shapes of the longitudinal profiles. For binary outcomes with the treatment effect on a single time point, the parametric model averaging method is recommended, while in the other cases the unmatched generalized pairwise comparison methodology is recommended. Both provide an easily interpretable effect size measure, and do not require exclusion of periods or subjects due toincompleteness.

Deacetylation via SIRT2 prevents keratin-mutation-associated injury and keratin aggregation.

Keratin (K) and other intermediate filament (IF) protein mutations at conserved arginines disrupt keratin filaments into aggregates and cause human epidermolysis bullosa simplex (EBS; K14-R125C) or predispose to mouse liver injury (K18-R90C). The challenge for more than 70 IF-associated diseases is the lack of clinically utilized IF-targeted therapies. We used high-throughput drug screening to identify compounds that normalized mutation-triggered keratin filament disruption. Parthenolide, a plant sesquiterpene lactone, dramatically reversed keratin filament disruption and protected cells and mice expressing K18-R90C from apoptosis. K18-R90C became hyperacetylated compared with K18-WT and treatment with parthenolide normalized K18 acetylation. Parthenolide upregulated the NAD-dependent SIRT2, and increased SIRT2-keratin association. SIRT2 knockdown or pharmacologic inhibition blocked the parthenolide effect, while site-specific Lys-to-Arg mutation of keratin acetylation sites normalized K18-R90C filaments. Treatment of K18-R90C-expressing cells and mice with nicotinamide mononucleotide had a parthenolide-like protective effect. In 2 human K18 variants that associate with human fatal drug-induced liver injury, parthenolide protected K18-D89H- but not K8-K393R-induced filament disruption and cell death. Importantly, parthenolide normalized K14-R125C-mediated filament disruption in keratinocytes and inhibited dispase-triggered keratinocyte sheet fragmentation and Fas-mediated apoptosis. Therefore, keratin acetylation may provide a novel therapeutic target for some keratin-associated diseases.

Epidermolysis Bullosa Simplex Caused by a Rare Homozygous Mutation in the EXPH5 Gene.

Recurrent blister formation in children may be a sign of hereditary epidermolysis bullosa even if no salient family history can be elicited. In a case of a 5-year-old boy with recurrent occasional skin blistering, we diagnosed epidermolysis bullosa simplex and found a causative rare homozygous mutation in EXPH5. Precise molecular genetic analysis is a prerequisite for the accurate diagnosis and adequate counselling of affected families.

Phenotype and genotype correlation of inherited epidermolysis bullosa in Indonesia.

Inherited epidermolysis bullosa (EB) is a group of genodermatoses with considerable clinical and genetic heterogeneity. Clinical diagnosis of the EB subtypes is frequently imprecise and requires confirmation with genetic testing. There is still limited study using genetic testing to identify EB subtypes in Indonesia. This study aims to identify the pathogenic variants of inherited EB patients at the Department of Dermatology and Venereology, Universitas Padjadjaran-Dr Hasan Sadikin General Hospital in Bandung, West Java, Indonesia and to describe the correlation between the phenotype and genotype of our patients. Twelve patients clinically diagnosed with EB were included in this study. Genetic testing was performed in collaboration with KK Women's and Children's Hospital, Singapore. Pathogenic variants were identified in the COL7A1 gene in seven patients, namely Dominant Dystrophic EB (DDEB) with mutation types c.5945G>T, c.6218G>A, Recessive Dystrophic EB (RDEB) c.2005C>T, c.6081dup, c.1268C>T, c.1784C>T which are all known mutations. Novel mutations were found in the COL7A1 gene in two patients namely DDEB c.6253G>T and RDEB c.6740C>T. Two EB Simplex (EBS) patients showed mutation KRT14 gene as c.356T>C, c.373C>T which are known mutation. In addition, a novel mutation in LAMA3 gene c.2649del was found in one Junctional EB (JEB) patient. The molecular diagnoses of 12 Indonesian EB patients were identified, of which three were novel pathogenic variants. Concordance between the initial clinical diagnosis and genetic testing was only 33%. This demonstrated the importance of early genetic testing for accurate diagnosis, prognostication, management and genetic counselling.