Prevalence of Dystrophic Epidermolysis Bullosa in Spain: A Population-Based Study Using the 3-Source Capture–Recapture Method. Evidence of a Need for Improvement in Care

Clinical Characteristics and Outcomes of Patients Hospitalized with Epidermolysis Bullosa: A Retrospective Population-Based Observational Study in Spain (2016-2021)

(1) Background: Epidermolysis bullosa (EB) comprises a group of rare skin diseases. We assessed diagnostic procedures, comorbidity profiles, length of hospital stay (LOHS), costs, and in-hospital mortality (IHM) associated with EB. (2) Methods: A retrospective, population-based observational study was performed using the Spanish National Hospital Discharge Database. Hospitalized patients with EB in Spain were identified for the period 2016 to 2021. (3) Results: A total of 677 hospitalizations were identified among 342 patients with a diagnosis of EB. Fifty percent of patients had at least one readmission during the 6-year follow-up. Notably, rehospitalizations were more common among patients aged 2-17 years. The most prevalent comorbidity was digestive disorders, which were associated with the frequency of esophageal dilatation procedures and percutaneous endoscopic gastrostomy. The longest LOHS was recorded for the 0- to 1-year age group. IHM increased with age, and the difference was statistically significant. The prevalence of malignant neoplasm was 36.88%, with cutaneous squamous cell carcinoma being the most frequent. The overall cost per hospitalized patient was estimated to be EUR 10,895.22 (SD EUR 13,394.81), with significant variations between age groups. (4) Conclusions: Readmissions are very frequent among people with EB. We observed a higher LOHS in the 0- to 1-year age group, while the highest rates of IHM were observed in patients older than 50 years. There was a substantial prevalence of comorbidities, namely, digestive disorders, infectious diseases, and especially cancer.

Biomarker Discovery in Rare Malignancies: Development of a miRNA Signature for RDEB-cSCC

Machine learning has been proven to be a powerful tool in the identification of diagnostic tumor biomarkers but is often impeded in rare cancers due to small patient numbers. In patients suffering from recessive dystrophic epidermolysis bullosa (RDEB), early-in-life development of particularly aggressive cutaneous squamous-cell carcinomas (cSCCs) represents a major threat and timely detection is crucial to facilitate prompt tumor excision. As miRNAs have been shown to hold great potential as liquid biopsy markers, we characterized miRNA signatures derived from cultured primary cells specific for the potential detection of tumors in RDEB patients. To address the limitation in RDEB-sample accessibility, we analyzed the similarity of RDEB miRNA profiles with other tumor entities derived from the Cancer Genome Atlas (TCGA) repository. Due to the similarity in miRNA expression with RDEB-SCC, we used HN-SCC data to train a tumor prediction model. Three models with varying complexity using 33, 10 and 3 miRNAs were derived from the elastic net logistic regression model. The predictive performance of all three models was determined on an independent HN-SCC test dataset (AUC-ROC: 100%, 83% and 96%), as well as on cell-based RDEB miRNA-Seq data (AUC-ROC: 100%, 100% and 91%). In addition, the ability of the models to predict tumor samples based on RDEB exosomes (AUC-ROC: 100%, 93% and 100%) demonstrated the potential feasibility in a clinical setting. Our results support the feasibility of this approach to identify a diagnostic miRNA signature, by exploiting publicly available data and will lay the base for an improvement of early RDEB-SCC detection.

Epidemiology of inherited epidermolysis bullosa in Germany

BACKGROUND

Epidermolysis bullosa (EB) is a rare genetic disorder manifesting with skin and mucosal membrane blistering in different degrees of severity.

OBJECTIVE

Epidemiological data from different countries have been published, but none are available from Germany.

METHODS

In this population-based cross-sectional study, people living with EB in Germany were identified using the following sources: academic hospitals, diagnostic laboratories and patient organization.

RESULTS

Our study indicates an overall EB incidence of 45 per million live births in Germany. With 14.23 per million live births for junctional EB, the incidence is higher than in other countries, possibly reflecting the availability of early molecular genetic diagnostics in severely affected neonates. Dystrophic EB was assessed at 15.58 cases per million live births. The relatively low incidence found for EB simplex, 14.93 per million live births, could be explained by late or missed diagnosis, but also by 33% of cases remaining not otherwise specified. Using log-linear models, we estimated a prevalence of 54 per million for all EB types, 2.44 for junctional EB, 12.16 for dystrophic EB and 28.44 per million for EB simplex. These figures are comparable to previously reported data from other countries.

CONCLUSIONS

Altogether, there are at least 2000 patients with EB in the German population. These results should support national policies and pharmaceutical companies in decision-making, allow more precise planning of drug development and clinical trials, and aid patient advocacy groups in their effort to improve quality of life of people with this orphan disease.

The epidemiology of epidermolysis bullosa in England and Wales: data from the national epidermolysis bullosa database

BACKGROUND

The NHS Epidermolysis Bullosa (EB) service set up in 2002 offers comprehensive, free care to all patients in England and Wales.

OBJECTIVE

To quantify prevalence, incidence and mortality of EB in England and Wales.

METHODS

Demographic data for patients in England and Wales was collected on a secure electronic database, prospectively from January 2002 to April 2021 and retrospectively before that. Vital status was verified using central NHS data.

RESULTS

By March 2021, 2594 individuals were registered, of whom 2361 were living, giving prevalence per million of the population for all EB types of 34.8; EB simplex (EBS) 17, dystrophic EB (DEB) 10.7, junctional EB (JEB) 1 and Kindler EB 0.3. We recorded 1200 babies with EB born since 2002, average incidence per million live births, for EBS, DEB, JEB and Kindler EB being 32.5, 26.1, 8.9, 0.9 respectively, total 67.8 for all types of EB. Birth rates fell progressively over the 19-year period for JEB-severe (JEB-S) (r = - 0.56) and recessive DEB-severe (RDEB-S) (r = -0.44) and also for milder types of EB. We observed longer survival in JEB-S over the 19 years (r² = 0.18) with a median of 12.7 months over the past 5 years.

CONCLUSIONS

We provide the first accurate epidemiological data for EB in England and Wales. We believe the observed reduction in birth incidence of severe types of EB reflects uptake of genetic counselling advice while that of milder types may be due to delayed presentation. A potential small trend towards longer survival of babies with JEB-S may reflect improved multidisciplinary care.

Epidemiological, clinical, pathological and genetic characteristics of epidermolysis bullosa in New Zealand

OBJECTIVE

To establish the epidemiological, clinical, pathological and genetic characteristics of epidermolysis bullosa (EB) in New Zealand (NZ).

METHODS

Participants were recruited through the Dystrophic Epidermolysis Bullosa Research Association of New Zealand (DEBRA NZ). Dedicated EB nurse medical records, Genetic Health Service NZ (GHSNZ) records and, where available, public hospital records were manually reviewed for relevant clinical data.

RESULTS

Ninety-two participants took part in the study (56% participation rate). Forty-nine (53%) participants had EB simplex (EBS), 40 (43%) had dystrophic EB (DEB), and 3 (3%) had junctional EB (JEB). Point prevalence for EB of all types was 19.5 per million, and 10.4, 8.6 and 0.9 per million for EBS, DEB and JEB, respectively. Thirty-four participants had intermediate or severe EB. There were 29 paediatric cases and almost even numbers of males and females. Compared to NZ European and Māori, prevalence rates were lower for Pacific and Asian people and higher in the Middle Eastern/Latin American/African population. Eight out of 14 skin biopsy results were informative, and 14 of 15 genetic test results were informative.

CONCLUSION

New Zealand has similar prevalence rates of EB compared with other national cohorts. This is likely to be an underestimate due to methodological limitations. Recent advancements in genomic testing have resulted in an improved diagnostic rate in our population. Further research into ethnic differences in prevalence, and exploring the characteristics of lethal forms of EB, is warranted. A dynamic registry may be helpful for the EB community in NZ.

Novel insights into the epidemiology of epidermolysis bullosa (EB) from the Dutch EB Registry: EB more common than previously assumed?

Background

Epidermolysis bullosa (EB) is a heterogeneous group of rare and incurable genetic disorders characterized by fragility of the skin and mucosae, resulting in blisters and erosions. Several epidemiological studies in other populations have been carried out, reporting varying and sometimes inconclusive figures, highlighting the need for standardized epidemiological analyses in well‐characterized cohorts.

Objectives

To evaluate the epidemiological data on EB in the Netherlands, extracted from the molecularly well‐characterized cohort in the Dutch EB Registry.

Methods

In this observational study all EB‐patients that were based in the Netherlands and captured in the Dutch EB Registry between 1988 and 2018 were included. The epidemiological outcomes were based on complete diagnostic data (clinical features, immunofluorescence, electron microscopy and mutation analysis), with longitudinal follow‐up.

Results

A total of 464 EB‐patients (287 families) were included. The incidence and point‐prevalence of EB in the Netherlands were 41.3 per million live births and 22.4 per million population, respectively. EB Simplex (EBS), Junctional EB (JEB), Dystrophic EB (DEB) and Kindler EB were diagnosed in 45.7%, 18.8%, 34.7% and 0.9% of the EB‐patients, respectively, with an incidence and point‐prevalence of 17.5 and 11.9 (EBS), 9.3 and 2.1 (JEB), 14.1 and 8.3 (DEB), 0.5 and 0.2 (Kindler EB). In 90.5% of the EB‐patients the diagnosis was genetically confirmed. During the investigated time period 73 EB‐patients died, 72.6% of whom as a direct consequence of their EB.

Conclusion

The epidemiological outcomes of EB in the Netherlands are high, attributed to a high detection rate in a well‐organized set‐up, indicating that EB might be more common than previously assumed. These epidemiological data help to understand the extensive need for (specialized) medical care of EB‐patients and is invaluable for the design and execution of therapeutic trials. This study emphasizes the importance of thorough reporting systems and registries worldwide.

Linked Commentary: L. Bruckner‐Tuderman. J Eur Acad Dermatol Venereol 2021; 35: 783–784. https://doi.org/10.1111/jdv.17165.

Consensus reclassification of inherited epidermolysis bullosa and other disorders with skin fragility

BACKGROUND

Several new genes and clinical subtypes have been identified since the publication in 2014 of the report of the last International Consensus Meeting on Epidermolysis Bullosa (EB).

OBJECTIVES

We sought to reclassify disorders with skin fragility, with a focus on EB, based on new clinical and molecular data.

METHODS

This was a consensus expert review.

RESULTS

In this latest consensus report, we introduce the concept of genetic disorders with skin fragility, of which classical EB represents the prototype. Other disorders with skin fragility, where blisters are a minor part of the clinical picture or are not seen because skin cleavage is very superficial, are classified as separate categories. These include peeling skin disorders, erosive disorders, hyperkeratotic disorders, and connective tissue disorders with skin fragility. Because of the common manifestation of skin fragility, these 'EB-related' disorders should be considered under the EB umbrella in terms of medical and socioeconomic provision of care.

CONCLUSIONS

The proposed classification scheme should be of value both to clinicians and researchers, emphasizing both clinical and genetic features of EB. What is already known about this topic? Epidermolysis bullosa (EB) is a group of genetic disorders with skin blistering. The last updated recommendations on diagnosis and classification were published in 2014. What does this study add? We introduce the concept of genetic disorders with skin fragility, of which classical EB represents the prototype. Clinical and genetic aspects, genotype-phenotype correlations, disease-modifying factors and natural history of EB are reviewed. Other disorders with skin fragility, e.g. peeling skin disorders, erosive disorders, hyperkeratotic disorders, and connective tissue disorders with skin fragility are classified as separate categories; these 'EB-related' disorders should be considered under the EB umbrella in terms of medical and socioeconomic provision of care. Linked Comment: Pope. Br J Dermatol 2020; 183:603.

From Clinical Phenotype to Genotypic Modelling: Incidence and Prevalence of Recessive Dystrophic Epidermolysis Bullosa (RDEB)

Background

Recessive dystrophic epidermolysis bullosa (RDEB) is an inherited genetic disorder characterized by recurrent and chronic open wounds with significant morbidity, impaired quality of life, and early mortality. RDEB patients demonstrate reduction or structural alteration type VII collagen (C7) owing to mutations in the gene COL7A1, the main component of anchoring fibrils (AF) necessary to maintain epidermal-dermal cohesion. While over 700 alterations in COL7A1 have been reported to cause dystrophic epidermolysis bullosa (DEB), which may be inherited in an autosomal dominant (DDEB) or autosomal recessive pattern (RDEB), the incidence and prevalence of RDEB is not well defined. To date, the widely estimated incidence (0.2–6.65 per million births) and prevalence (3.5–20.4 per million people) of RDEB has been primarily characterized by limited analyses of clinical databases or registries.

Methods

Using a genetic modelling approach, we use whole exome and genome sequencing data to estimate the allele frequency of pathogenic variants. Through the ClinVar and NCBI database of human genome variants and phenotypes, DEB Register, and analyzing premature COL7A1 termination variants we built a model to predict the pathogenicity of previously unclassified variants. We applied the model to publicly available sequences from the Exome Aggregation Consortium (ExAC) and Genome Aggregation Database (gnomAD) and identified variants which were classified as pathogenic for RDEB from which we estimate disease incidence and prevalence.

Results

Genetic modelling applied to the whole exome and genome sequencing data resulted in the identification of predicted RDEB pathogenic alleles, from which our estimate of the incidence of RDEB is 95 per million live births, 30 times the 3.05 per million live birth incidence estimated by the National Epidermolysis Bullosa Registry (NEBR). Using a simulation approach, we estimate a mean of approximately 3,850 patients in the US who may benefit from COL7A1-mediated treatments in the US.

Conclusion

We conclude that genetic allele frequency estimation may enhance the underdiagnosis of rare genetic diseases generally, and RDEB specifically, which may improve incidence and prevalence estimates of patients who may benefit from treatment.

Epidermolysis Bullosa-Associated Squamous Cell Carcinoma: From Pathogenesis to Therapeutic Perspectives

Epidermolysis bullosa (EB) is a heterogeneous group of inherited skin disorders determined by mutations in genes encoding for structural components of the cutaneous basement membrane zone. Disease hallmarks are skin fragility and unremitting blistering. The most disabling EB (sub)types show defective wound healing, fibrosis and inflammation at lesional skin. These features expose patients to serious disease complications, including the development of cutaneous squamous cell carcinomas (SCCs). Almost all subjects affected with the severe recessive dystrophic EB (RDEB) subtype suffer from early and extremely aggressive SCCs (RDEB-SCC), which represent the first cause of death in these patients. The genetic determinants of RDEB-SCC do not exhaustively explain its unique behavior as compared to low-risk, ultraviolet-induced SCCs in the general population. On the other hand, a growing body of evidence points to the key role of tumor microenvironment in initiation, progression and spreading of RDEB-SCC, as well as of other, less-investigated, EB-related SCCs (EB-SCCs). Here, we discuss the recent advances in understanding the complex series of molecular events (i.e., fibrotic, inflammatory, and immune processes) contributing to SCC development in EB patients, cross-compare tumor features in the different EB subtypes and report the most promising therapeutic approaches to counteract or delay EB-SCCs.

Genetic diagnosis of epidermolysis bullosa: recommendations from an expert Spanish research group

Epidermolysis bullosa (EB) is a rare genetic disease that causes mucocutaneous fragility. It comprises a clinically and genetically heterogeneous group of disorder characterized by spontaneous or contact/friction-induced blistering. EB is classified into 4 types-simplex, junctional, dystrophic, and Kindler syndrome-and 30 subtypes. The disease is caused by defects in proteins implicated in dermal-epidermal adhesion. At least 19 genes have been characterized and more than 1000 mutations identified, thus rendering diagnosis complex. Molecular diagnosis of EB is the last stage of a laborious process that starts with a detailed clinical history compilation and careful procurement of a skin fresh biopsy that includes an area where the epidermis detaches from the dermis. The detachment area makes it possible to establish the cleavage plane by antigen mapping and, in the best scenario, to identify a single candidate gene to search for pathogenic mutations. The results of the molecular diagnosis enable the physician to provide appropriate genetic counseling (inheritance pattern, risk of recurrence, and options for prenatal and preimplantation diagnosis) and implement subsequent preventive programs, as well as to establish a reasonable clinical prognosis facilitating access to specific therapy and rehabilitation. Lastly, molecular diagnosis is essential for the participation of patients in clinical trials, a critical issue given the current incurable status of EB. The present guidelines aim to disseminate the procedure for diagnosing EB in our laboratory and thus avoid suboptimal or incomplete clinical diagnoses. The recommendations we provide are the result of more than 10 years' experience in the molecular diagnosis of EB in Spain.

Identification of tissue damage, extracellular matrix remodeling and bacterial challenge as common mechanisms associated with high-risk cutaneous squamous cell carcinomas

In this study we used a genetic extracellular matrix (ECM) disease to identify mechanisms associated with aggressive behavior of cutaneous squamous cell carcinoma (cSCC). cSCC is one of the most common malignancies and usually has a good prognosis. However, some cSCCs recur or metastasize and cause significant morbidity and mortality. Known factors that are associated with aggressiveness of cSCCs include tumor grading, size, localization and microinvasive behavior. To investigate molecular mechanisms that influence biologic behavior we used global proteomic and histologic analyses of formalin-fixed paraffin-embedded tissue of primary human cSCCs. We compared three groups: non-recurring, non-metastasizing low-risk sporadic cSCCs; metastasizing sporadic cSCCs; and cSCCs from patients with recessive dystrophic epidermolysis bullosa (RDEB). RDEB is a genetic skin blistering and ECM disease caused by collagen VII deficiency. Patients commonly suffer from high-risk early onset cSCCs that frequently metastasize. The results indicate that different processes are associated with formation of RDEB cSCCs compared to sporadic cSCCs. Sporadic cSCCs show signs of UV damage, whereas RDEB cSCCs have higher mutational rates and display tissue damage, inflammation and subsequent remodeling of the dermal ECM as tumor initiating factors. Interestingly the two high-risk groups - high-risk metastasizing sporadic cSCCs and RDEB cSCCs - are both associated with tissue damage and ECM remodeling in gene-ontology enrichment and Search Tool for the Retrieval of Interacting Genes/Proteins analyses. In situ histologic analyses validate these results. The high-risk cSCCs also show signatures of enhanced bacterial challenge. Histologic analyses confirm correlation of bacterial colonization with worse prognosis. Collectively, this unbiased study - performed directly on human patient material - reveals that common microenvironmental alterations linked to ECM remodeling and increased bacterial challenges are denominators of high-risk cSCCs. The proteins identified here could serve as potential diagnostic markers and therapeutic targets in high-risk cSCCs.

Prevalence of hereditary epidermolysis bullosa in the Russian Federation

Goal. To study the prevalence of hereditary epidermolysis bullosa (HEB) in the Russian Federation. Materials and methods. The data on the number of HEB patients by subjects of the Russian Federation as well as their age and disease type were obtained based on questionnaires. The questionnaires were sent to dermatovenerology healthcare institutions from 85 subjects of the Russian Federation. The HEB prevalence rates in the subjects of the Russian Federation were calculated as the ratio of the number of HEB patients in the subject of the Russian Federation to the population size in the subject per million residents. Results. Information about 438 HEB patients (210 female and 228 male) aged 0-66 was collected in 70 subjects of the Russian Federation as of January 1, 2015. The disease type was specified for 139 patients (86 patients with common HEB, 50 patients with dystrophic HEB and 3 patients with the borderline form of HEB). No details about the disease type were provided for 299 patients (68.26%). The HEB prevalence rate in the subjects of the Russian Federation varies from 0 to 19.73 cases per million residents. Conclusion. These data on the HEB prevalence rate in 70 subjects of the Russian Federation are comparable to the data specified in literature sources providing information on the HEB prevalence rate in some foreign states. The data represent the first step to the development of clinical recommendations concerning HEB management and establishment of a register of in the Russian Federation.