Otological complications in inversa type recessive dystrophic epidermolysis bullosa.

BACKGROUND: The rare inversa subtype of recessive dystrophic epidermolysis bullosa (RDEB-I) is characterized by predominant intertriginous skin blistering and marked mucosal involvement. Specific recessive missense mutations in the collagen VII triple helix are implicated in the disease. To date, otological complications have been reported infrequently in this patient group. METHODS: We conducted an observational, retrospective, double institution case record review of patients with RDEB-I who presented with otological complications between January 2000 and June 2020. Diagnosis was established on the basis of clinical features, family history and mutation analysis of the COL7A1 gene. RESULTS: In total, 11 (44%) of 25 patients with RDEB-I in our database (2 paediatric, 9 adult; mean age 40.9 years, range 8-72 years) experienced otological complications. Of these 11 patients, 10 (90.9%) had recurrent otitis externa, 7 (63.6%) had meatal stenosis and 7 (63.6%) had recurrent blistering of the external auditory canals. All 11 patients reported hearing difficulties, with conductive hearing loss confirmed by audiology testing in 6 (54.5%) of these. Of the 11 patients, 3 (27.3%) went on to have implantable hearing aids [2 bone-anchored hearing aids (BAHA) and 1 middle ear implant (MEI)] fitted with favourable outcome, while a fourth paediatric patient presented with a cholesteatoma that was surgically managed. DISCUSSION: We observed a higher prevalence of otological morbidity in RDEB-I than previously reported, and present the first case of cholesteatoma in epidermolysis bullosa (EB). Our data indicate that BAHA and MEI are safe and effective treatment options for hearing loss in EB. Clinicians should be vigilant in screening for ear symptoms in RDEB-I and consider early referral to an Ear, Nose and Throat specialist.

Prevalence, pathophysiology and management of itch in epidermolysis bullosa.

Epidermolysis bullosa (EB) is a highly diverse group of inherited skin disorders, resulting from mutations in genes encoding proteins of the dermoepidermal junction. Itch (pruritus) is one of the most common symptoms across all EB subtypes. It occurs in blistered or wounded sites, or manifests as a generalized phenomenon, thereby affecting both intact skin and healing wounds. The mechanism of pruritus in EB is unclear. It is likely that skin inflammation secondary to barrier disruption, wound healing cascades and dysregulated activation of epidermal sensory nerve endings are all involved in its pathophysiology on the molecular and cellular level. Understanding these mechanisms in depth is crucial in developing optimized treatments for people with EB and improving quality of life. This review summarizes current evidence on the prevalence, mechanisms and management of itch in EB.

Heterogeneous addiction to transforming growth factor-beta signalling in recessive dystrophic epidermolysis bullosa-associated cutaneous squamous cell carcinoma.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is associated with a high mortality rate due to the development of life-threatening, metastatic cutaneous squamous cell carcinoma (cSCC). Elevated transforming growth factor-beta (TGF-ß) signalling is implicated in cSCC development and progression in patients with RDEB. OBJECTIVES: To determine the effect of exogenous and endogenous TGF-ß signalling in RDEB cSCC with a view to assessing the potential of targeting TGF-ß signalling for RDEB cSCC therapy. METHODS: A panel of 11 patient-derived RDEB cSCC primary tumour keratinocyte cell lines (SCCRDEBs) were tested for their signalling and proliferation responses to exogenous TGF-ß. Their responses to TGF-ß receptor type-1 (TGFBR1) kinase inhibitors [SB-431542 and AZ12601011 (AZA01)] were tested using in vitro proliferation, clonogenicity, migration and three-dimensional invasion assays, and in vivo tumour xenograft assays. RESULTS: All SCCRDEBs responded to exogenous TGF-ß by activation of canonical SMAD signalling and proliferative arrest. Blocking endogenous signalling by treatment with SB-431542 and AZ12601011 significantly inhibited proliferation (seven of 11), clonogenicity (six of 11), migration (eight of 11) and invasion (six of 11) of SCCRDEBs. However, these TGFBR1 kinase inhibitors also promoted proliferation and clonogenicity in two of 11 SCCRDEB cell lines. Pretreatment of in vitro TGFBR1-addicted SCCRDEB70 cells with SB-431542 enhanced overall survival and reduced tumour volume in subcutaneous xenografts but had no effect on nonaddicted SCCRDEB2 cells in these assays. CONCLUSIONS: Targeting TGFBR1 kinase activity may have therapeutic benefit in the majority of RDEB cSCCs. However, the potential tumour suppressive role of TGF-ß signalling in a subset of RDEB cSCCs necessitates biomarker identification to enable patient stratification before clinical intervention.

Practical management of epidermolysis bullosa: consensus clinical position statement from the European Reference Network for Rare Skin Diseases.

Inherited epidermolysis bullosa (EB) comprises rare disorders that manifest with fragility and blistering of the skin and mucous membranes, with variable clinical severity. Management of EB is challenging due to disease rarity and complexity, the wide range of extracutaneous manifestations and a profound impact on daily life for the patient and family members. Although reference centres providing multidisciplinary care for EB exist in each European country, it is common for healthcare professionals that are not specialized in this rare disorder to treat EB patients. Here, experts of the European Reference Network for Rare and Undiagnosed Skin Diseases (ERN-Skin, https://ern-skin.eu) propose practical recommendations for the diagnosis and management of the commonest clinical issues, skin blisters and wounds, oral manifestations, pain and itch.

Foot care in epidermolysis bullosa: evidence-based guideline.

This guideline was designed to provide service providers and users with an evidence-based set of current best practice guidelines for people and their families and carers, living with epidermolysis bullosa (EB). A systematic literature review relating to the podiatric care of patients with EB was undertaken. Search terms were used, for which the most recent articles relating to podiatric treatment were identified from as early as 1979 to the present day, across seven electronic search engines: MEDLINE, Wiley Online Library, Google Scholar, Athens, ResearchGate, Net and PubFacts.com. The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used. The first guideline draft was analysed and discussed by clinical experts, methodologists and patients and their representatives at four panel meetings. The resulting document went through an external review process by a panel of experts, other healthcare professionals, patient representatives and lay reviewers. The final document will be piloted in three different centres in the U.K. and Australia. Following an EB community international survey the outcomes indicated six main areas that the community indicated as a priority to foot management. These include blistering and wound management, exploring the most suitable footwear and hosiery for EB, management of dystrophic nails, hyperkeratosis (callus), maintaining mobility and fusion of toes (pseudosyndactyly). The evidence here is limited but several interventions currently practised by podiatrists show positive outcomes.

Creating new guidelines on how best to treat foot symptoms in people with EB.

Epidermolysis bullosa (EB) is a complex rare condition that affects the skin and many parts of the body. Those born with EB have skin so fragile they are called 'butterfly children', their skin is quite simply as fragile as the wing of a butterfly. In the UK it is estimated that there are more than 5,000 people living with EB and 500,000 worldwide. Little clinical guidance for care existed until DEBRA International started a programme to develop clinical practice guidelines (CPGs). There were no previous guidelines and few published studies on foot care in EB so treatment decisions were largely based on individual opinion and experience. The panel - made up of clinical experts and people living with EB representing Australia, the UK, and the USA - aimed to describe foot problems in people of all ages with EB, and summarise current evidence and management. The authors used a logical podiatric (foot) care literature review focussed on patients with EB. The authors found that the evidence in this area was limited but several interventions (treatments) currently practised by podiatrists show positive outcomes. The study allowed the group to make recommendations on how to treat foot and nail disorders in patients with EB. Furthermore, the authors concluded that further research is needed. This is a summary of the study: Foot care in epidermolysis bullosa: evidence-based guideline.

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.

Genotype-phenotype correlation in a large English cohort of patients with autosomal recessive ichthyosis.

BACKGROUND: Recessive forms of congenital ichthyosis encompass a group of rare inherited disorders of keratinization leading to dry, scaly skin. So far, 13 genes have been implicated, but there is a paucity of data on genotype-phenotype correlation in some populations. OBJECTIVES: We compiled an English cohort of 146 individuals with recessive ichthyosis and assessed genotype-phenotype correlation. METHODS: Deep phenotyping was undertaken by history-taking and clinical examination. DNA was screened for mutations using a next-generation sequencing ichthyosis gene panel and Sanger sequencing. RESULTS: Cases were recruited from 13 National Health Service sites in England, with 65% of patients aged < 16 years at enrolment. Pathogenic biallelic mutations were found in 83% of cases, with the candidate gene spread as follows: TGM1 29%, NIPAL4 12%, ABCA12 12%, ALOX12B 9%, ALOXE3 7%, SLC27A4 5%, CERS3 3%, CYP4F22 3%, PNPLA1 2%, SDR9C7 1%. Clinically, a new sign, an anteriorly overfolded ear at birth, was noted in 43% of patients with ALOX12B mutations. The need for intensive care stay (P = 0·004), and hand deformities (P < 0·001), were associated with ABCA12 mutations. Self-improving collodion ichthyosis occurred in 8% of the cases (mostly TGM1 and ALOX12B mutations) but could not be predicted precisely from neonatal phenotype or genotype. CONCLUSIONS: These data refine genotype-phenotype correlation for recessive forms of ichthyosis in England, demonstrating the spectrum of disease features and comorbidities, as well as the gene pathologies therein. Collectively, the data from these patients provide a valuable resource for further clinical assessment, improving clinical care and the possibility of future stratified management. What's already known about this topic? Recessive forms of ichthyosis are rare but often difficult to diagnose. Mutations in 13 genes are known to cause recessive forms of ichthyosis: ABCA12, ALOX12B, ALOXE3, CERS3, CYP4F22, LIPN, NIPAL4, PNPLA1, SDR9C7, SLC27A4, SULT2B1, ST14 and TGM1. Some phenotypic features may associate with certain gene mutations, but paradigms for genotype-phenotype correlation need refining. What does this study add? The genotypic spectrum of recessive ichthyosis in England (based on 146 cases) comprises TGM1 (29%), NIPAL4 (12%), ABCA12 (12%), ALOX12B (9%), ALOXE3 (7%), SLC27A4 (5%), CERS3 (3%), CYP4F22 (3%), PNPLA1 (2%) and SDR9C7 (1%). New or particular phenotypic clues were defined for mutations in ALOX12B, ABCA12, CYP4F22, NIPAL4, SDR9C7 and TGM1, either in neonates or in later life, which allow for greater diagnostic precision. In around 17% of cases, the molecular basis of recessive ichthyosis remains unknown.

Management of cutaneous squamous cell carcinoma in patients with epidermolysis bullosa: best clinical practice guidelines.

This article summarizes recommendations reached following a systematic literature review and expert consensus on the diagnosis and management of cutaneous squamous cell carcinomas in people with epidermolysis bullosa. The guidelines are intended to help inform decision making by clinicians dealing with this complex complication of a devastating disease.

Whole-exome sequencing improves mutation detection in a diagnostic epidermolysis bullosa laboratory.

BACKGROUND: Subtypes of inherited epidermolysis bullosa (EB) vary significantly in their clinical presentation and prognosis. Establishing an accurate diagnosis is important for genetic counselling and patient management. Current approaches in EB diagnostics involve skin biopsy for immunohistochemistry and transmission electron microscopy, and Sanger sequencing of candidate genes. Although informative in most cases, this approach can be expensive and laborious and may fail to identify pathogenic mutations in ~15% of cases. OBJECTIVES: Next-generation DNA sequencing (NGS) technologies offer a fast and efficient complementary diagnostic strategy, but the value of NGS in EB diagnostics has yet to be explored. The aim of this study was to undertake whole-exome sequencing (WES) in nine cases of EB in which established diagnostic methods failed to make a genetic diagnosis. METHODS: Whole-exome capture was performed using genomic DNA from each case of EB, followed by massively parallel sequencing. Resulting reads were mapped to the human genome reference hg19. Potentially pathogenic mutations were subsequently confirmed by Sanger sequencing. RESULTS: Analysis of WES data disclosed biallelic pathogenic mutations in each case, with all mutations occurring in known EB genes (LAMB3, PLEC, FERMT1 and COL7A1). This study demonstrates that NGS can improve diagnostic sensitivity in EB compared with current laboratory practice. CONCLUSIONS: With appropriate diagnostic platforms and bioinformatics support, WES is likely to increase mutation detection in cases of EB and improve EB diagnostic services, although skin biopsy remains an important diagnostic investigation in current clinical practice.

Clinical features and WNT10A mutations in seven unrelated cases of Schöpf-Schulz-Passarge syndrome.

BACKGROUND: Schöpf-Schulz-Passarge syndrome (SSPS) is an autosomal recessive form of ectodermal dysplasia resulting from mutations in WNT10A. OBJECTIVES: To document the spectrum of clinical features and search for pathogenic mutations in seven unrelated cases of SSPS. METHODS: Clinical examination of patients and Sanger sequencing of genomic DNA spanning the coding exons and flanking spice sites of WNT10A. RESULTS: Most subjects had bilateral eyelid cysts and some degree of palmoplantar keratoderma, although nail, hair, and teeth abnormalities were variably present. Bi-allelic pathogenic mutations in WNT10A were found in all seven subjects. New mutations comprised p.Glu390*, p.Ser270Arg, and p.Cys362Arg; the recurrent mutations were p.Cys107* and p.Ala131Thr. CONCLUSIONS: This study reveals the range of ectodermal pathology in cases of SSPS that result from WNT10A mutations. Eyelid cysts provide a useful clinical clue to diagnosing SSPS which may be less rare than is currently appreciated.

Mutations in EXPH5 result in autosomal recessive inherited skin fragility.

Several different genes have been implicated in the pathophysiology of inherited blistering skin diseases. Recently, autosomal recessive loss-of-function mutations in EXPH5 (encoding exophilin-5, also known as Slac2-b, a protein involved in intracellular vesicle transport) were identified in a new mechanobullous disease resembling a form of epidermolysis bullosa simplex (EBS). Here, we searched for mutations in EXPH5 in a 4-year-old white boy with EBS in whom initial Sanger sequencing of known genes implicated in intraepidermal skin fragility failed to identify pathogenic mutations. Transmission electron microscopy of rubbed nonlesional patient skin revealed disruption of keratinocytes in the lower epidermis with cytolysis and acantholysis, keratin filament clumping and prominent perinuclear cytoplasmic vesicles, and provided the clue to the candidate gene pathology. Sanger sequencing of genomic DNA showed compound heterozygosity for two new mutations in EXPH5, c.1947dupC (p.Pro649fsPro*11) and c.2249C>A (p.Ser750*). Immunofluorescence microscopy of patient skin showed a complete absence of exophilin-5 labelling. This case represents the third pedigree with EXPH5 mutations resulting in inherited skin fragility. The clinical and molecular data expand genotype-phenotype correlation in this new form of EBS and demonstrate the important role of exophilin-5 in keratinocyte cell biology.