Dystrophic epidermolysis bullosa pruriginosa in Italy: clinical and molecular characterization

Pruritus Anesis in Dystrophic Epidermolysis Bullosa Pruriginosa with Dupilumab

ABSTRACT

Dystrophic epidermolysis bullosa pruriginosa (DEB-Pr) is a rare subtype of dystrophic epidermolysis bullosa, and traditional treatments have limited efficacy. Dupilumab has demonstrated remarkable efficacy in relieving pruritus. In this case study, after traditional treatment failed, providers recommended the patient begin dupilumab to treat his pruritus. The patient was administrated a loading dose of 600 mg of dupilumab and a dose of 300 mg every 2 weeks. The Dermatology Life Quality Index and Pruritic Numeric Rating Scale were used to assess the patient's situation. After several months, the patient's DEB-Pr was considered in remission. Dupilumab may be a better choice than immunosuppressants for the treatment of pruritus in patients with DEB-Pr.

Epidermolysis Bullosa—A Different Genetic Approach in Correlation with Genetic Heterogeneity

Epidermolysis bullosa is a heterogeneous group of rare genetic disorders characterized by mucocutaneous fragility and blister formation after minor friction or trauma. There are four major epidermolysis bullosa types based on the ultrastructural level of tissue cleavage: simplex, junctional, dystrophic, and Kindler epidermolysis bullosa. They are caused by mutations in genes that encode the proteins that are part of the hemidesmosomes and focal adhesion complex. Some of these disorders can be associated with extracutaneous manifestations, which are sometimes fatal. They are inherited in an autosomal recessive or autosomal dominant manner. This review is focused on the phenomena of heterogeneity (locus, allelic, mutational, and clinical) in epidermolysis bullosa, and on the correlation genotype–phenotype.

Dystrophic epidermolysis bullosa pruriginosa: a new case series of a rare phenotype unveils skewed Th2 immunity

BACKGROUND

Dystrophic epidermolysis bullosa pruriginosa (DEB-Pr) is a rare subtype of hereditary epidermolysis bullosa, with a poorly understood pathogenesis and no satisfactory treatment.

OBJECTIVES

To assess the clinical and biological features, genetic basis and therapeutic management, to better characterize this rare genodermatosis.

METHODS

We have conducted a retrospective study, reviewing the clinical presentation, genetic diagnosis, immunohistopathological findings and biological characteristics and management of patients with dystrophic epidermolysis bullosa pruriginosa. This study was conducted in the Department of Dermatology at Saint-Louis Hospital and the Department of Genetics at Necker Hospital (Paris, France). All patients with a diagnosis of DEB-Pr seen between 2010 and 2020 were included.

RESULTS

Seven patients were included, the average age of 50.1 years [range 36-76]. Pruriginous-lichenified papules, plaques or nodules appeared at 27.6 years on average [range 7-66] on pretibial areas and forearms, associated with milia and toenails dystrophy. All patients received multiple treatments, but none could sustainably reduce pruritus. Immunohistopathological analysis of lesion skin revealed subepidermal blister with fibrosis, milia and mast cell infiltration. Serum TNFα, IL1β and IL6 levels were elevated in 2/6 patients. Total serum IgE levels were increased in 7/7 patients, with no history of atopy. Immunophenotyping of circulating T-cells revealed an increased Th2 subset in 4/4 patients, with reduced Th1 and Th17 subpopulations. Genetic analysis of COL7A1 identified 7 distinct causative mutations, six of which were new. Intra-familial clinical variability was documented in 5/7 patients and was associated with the co-inheritance of a recessive COL7A1 mutation or an FLG2 mutation in 2 families.

CONCLUSION

Our study confirms the stereotyped presentation of DEB-Pr with large intra-familial variability in disease expression. Mast cell infiltration, elevated IgE and increased Th2 subset without atopy strongly support a role of Th2-mediated immunity in DEB-Pr, and further argue for new targeted therapeutic options such as dupilumab.

Genodermatoses with itch as a prominent feature

A number of inherited conditions cause chronic itch as a part of the recognized phenotype. Advances in the understanding of the genetic factors that cause these diseases elucidate the molecular underpinning of itch as a symptom. Our knowledge of the causes of chronic itch has also advanced, providing an opportunity to integrate the genetic pathophysiology with the molecular landscape of chronic itch mediators. This article reviews select genodermatoses that have itch as a predominant feature with a focus on the pathophysiology of the disease, how it may lead to itch and potential therapeutic targets.

Natural Exon Skipping Sets the Stage for Exon Skipping as Therapy for Dystrophic Epidermolysis Bullosa

Dystrophic epidermolysis bullosa (DEB) is a devastating blistering disease affecting skin and mucous membranes. It is caused by pathogenic variants in the COL7A1 gene encoding type VII collagen, and can be inherited dominantly or recessively. Recently, promising proof-of-principle has been shown for antisense oligonucleotide (AON)-mediated exon skipping as a therapeutic approach for DEB. However, the precise phenotypic effect to be anticipated from exon skipping, and which patient groups could benefit, is not yet clear. To answer these questions, we studied new clinical and molecular data on seven patients from the Dutch EB registry and reviewed the literature on COL7A1 exon skipping variants. We found that phenotypes associated with dominant exon skipping cannot be distinguished from phenotypes caused by other dominant DEB variants. Recessive exon skipping phenotypes are generally relatively mild in the spectrum of recessive DEB. Therefore, for dominant DEB, AON-mediated exon skipping is unlikely to ameliorate the phenotype. In contrast, the overall severity of phenotypes associated with recessive natural exon skipping pivots toward the milder end of the spectrum. Consequently, we anticipate AON-mediated exon skipping for recessive DEB caused by bi-allelic null variants should lead to a clinically relevant improvement of this devastating phenotype.

Epidermolysis bullosa pruriginosa: A rare entity which responded well to thalidomide

Epidermolysis bullosa pruriginosa is an unusual clinical variant of dystrophic epidermolysis bullosa characterized by sublamina densa blistering and intense pruritus leading to hypertrophic lichenoid nodules, plaques, milia, and variable presence of albopapuloid lesions. Most cases are sporadic but a few cases have autosomal dominant or recessive inheritance. Treatment has been quite disappointing and failed to produce satisfactory or sustained results. We report a case of 39-years-old male with epidermolysis bullosa pruriginosa and its response to thalidomide.

Epidermolysis bullosa pruriginosa: a systematic review exploring genotype-phenotype correlation

INTRODUCTION

Epidermolysis bullosa pruriginosa (EBP) is a clinical variant of dystrophic epidermolysis bullosa (DEB), characterized by intense pruritus and hypertrophic, lichenified, prurigo-like papules, plaques, and nodules secondary to scratching. These clinical findings have been attributed to various mutations in the COL7A1 gene. Previous reports have yielded inconsistent findings regarding a possible genotype-phenotype relationship in EBP.

OBJECTIVE

Our aim was to conduct a systematic review aimed at assessing the genotype-phenotype correlation in EBP.

METHODS

A systematic review was conducted using PubMed, Medline, EMBASE, and Cochrane databases for all reports of mutation-verified EBP, published from 1946 to September 2014. Statistical comparison of clinical findings between mutation types was performed using logistic regression analysis.

RESULTS

The review included a total of 28 articles with 74 individuals, which consisted of level 4 non-controlled case series (grade C) and level 5 case reports (grade D). Previous reported mutation types included glycine substitution (GS, 52.7%), in-frame skipping (IFS, 33.8%), non-glycine substitution (NGS, 8.1%), and premature termination codon (PTC, 5.4%). The most common clinical findings were extremities involvement, linear configuration, and nail dystrophy. In comparison with GS mutation carriers, IFS carriers had a higher likelihood of (1) being male (OR 2.99; p = 0.043; 95% CI 1.27-11.4) and (2) presenting with blisters (OR 4.10; p = 0.013; 95% CI 1.34-12.5).

CONCLUSIONS

To our knowledge, this study is the first systematic review examining the relationship between mutation type and clinical presentation in EBP. The findings in this review (1) identify common clinical characteristics of EBP that may help in the assessment of patients with possible EBP; and (2) indicate that certain mutation carriers may have a higher likelihood of exhibiting particular phenotypes. In the case of potential diagnostic challenge, assessment for presence of common clinical findings as well as molecular testing may facilitate correct identification and prognostication.

Multicentre consensus recommendations for skin care in inherited epidermolysis bullosa

Background

Inherited epidermolysis bullosa (EB) comprises a highly heterogeneous group of rare diseases characterized by fragility and blistering of skin and mucous membranes. Clinical features combined with immunofluorescence antigen mapping and/or electron microscopy examination of a skin biopsy allow to define the EB type and subtype. Molecular diagnosis is nowadays feasible in all EB subtypes and required for prenatal diagnosis. The extent of skin and mucosal lesions varies greatly depending on EB subtype and patient age. In the more severe EB subtypes lifelong generalized blistering, chronic ulcerations and scarring sequelae lead to multiorgan involvement, major morbidity and life-threatening complications. In the absence of a cure, patient management remains based on preventive measures, together with symptomatic treatment of cutaneous and extracutaneous manifestations and complications. The rarity and complexity of EB challenge its appropriate care. Thus, the aim of the present study has been to generate multicentre, multidisciplinary recommendations on global skin care addressed to physicians, nurses and other health professionals dealing with EB, both in centres of expertise and primary care setting.

Methods

Almost no controlled trials for EB treatment have been performed to date. For this reason, recommendations were prepared by a multidisciplinary team of experts from different European EB centres based on available literature and expert opinion. They have been subsequently revised by a panel of external experts, using an online-modified Delphi method to generate consensus.

Results

Recommendations are reported according to the age of the patients. The major topics treated comprise the multidisciplinary approach to EB patients, global skin care including wound care, management of itching and pain, and early diagnosis of squamous cell carcinoma. Aspects of therapeutic patient education, care of disease burden and continuity of care are also developed.

Conclusion

The recommendations are expected to be useful for daily global care of EB patients, in particular in the community setting. An optimal management of patients is also a prerequisite to allow them to benefit from the specific molecular and cell-based treatments currently under development.

Epidermolysis bullosa pruriginosa: further clarification of the phenotype

A defect in type VII collagen causes dystrophic epidermolysis bullosa (DEB). The pruriginosa variant (DEB-Pr) is unique because its initial presentation may be delayed until adolescence or adulthood, and its predominant feature is scarring and pruritus without the characteristic skin fragility of DEB. We describe three families with multiple affected members in which DEB-Pr shows an autosomal-dominant inheritance pattern. All affected individuals were examined, and three previously unreported COL7A1 mutations were identified.

An incompletely penetrant novel mutation in COL7A1 causes epidermolysis bullosa pruriginosa and dominant dystrophic epidermolysis bullosa phenotypes in an extended kindred

Epidermolysis bullosa pruriginosa (EBP) is a rare subtype of dystrophic epidermolysis bullosa (DEB) characterized by intense pruritus, nodular or lichenoid lesions, and violaceous linear scarring, most prominently on the extensor extremities. Remarkably, identical mutations in COL7A1, which encodes an anchoring fibril protein present at the dermal-epidermal junction, can cause both DEB and EBP with either autosomal dominant or recessive inheritance. We present one family with both dystrophic and pruriginosa phenotypes of epidermolysis bullosa. The proband is a 19-year-old Caucasian woman who initially presented in childhood with lichenoid papules affecting her extensor limbs and intense pruritus consistent with EBP. Her maternal grandmother saw a dermatologist for similar skin lesions that developed without any known triggers at age 47 and mostly resolved spontaneously after approximately 10 years. The proband's younger brother developed a small crop of pruritic papules on his elbows, dorsal hands, knees, and ankles at age 13. Her second cousin once removed, however, reported a mild blistering disease without pruritus consistent with DEB. Genetic sequencing of the kindred revealed a single dominant novel intron 47 splice site donor G>A mutation, c.4668 + 1 G>A, which we predict leads to exon skipping. Incomplete penetrance is confirmed in her clinically unaffected mother, who carries the same dominant mutation. The wide diversity of clinical phenotypes with one underlying genotype demonstrates that COL7A1 mutations are incompletely penetrant and strongly suggests that other genetic and environmental factors influence clinical presentation.

Exon 87 skipping of the COL7A1 gene in dominant dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa (DEB) is a rare, inherited, blistering disorder resulting from mutations in the COL7A1 gene, which encodes the anchoring fibrils, type VII collagen. We herein describe a further Japanese girl diagnosed with dominant DEB (DDEB). She had blisters sporadically and erosions healed with mild scarring and milia on the knees and pretibial regions. Severe pruritus was present at this time. Direct nucleotide sequencing of genomic DNA disclosed a heterozygous same splice-site mutation c.6900G>A in the COL7A1, which causes in-frame exon 87 skipping. So far, five different COL7A1 mutations leading to exon 87 skipping have been identified in rare forms of DEB: four DDEB pruriginosa and one pretibial DDEB. Therefore, a recent study suggested that exon 87 skipping in COL7A1 was related to the phenotype of DDEB pruriginosa. When she was 18 years old, however, the blister formation and pruritus markedly decreased. Therefore, her clinical symptoms were consistent to very mild DDEB but not to DDEB pruriginosa. Taken together, in-frame exon 87 skipping through c.6900G>A mutation may account for the mild skin features, rather than DDEB pruriginosa, in the present case.