Transient bullous dermolysis of the newborn in three generations

Self-improving dystrophic epidermolysis bullosa with a novel heterozygous missense variant in the COL7A1 gene in a Taiwanese family

Self-improving dystrophic epidermolysis bullosa (DEB) is a genodermatosis that is inherited autosomal dominantly or recessively, and its clinical symptoms may improve or subside spontaneously. Herein, we report a case of self-improving DEB with COL7A1 p.Gly2025Asp variant. The diagnosis was made through histopathological, electron microscopic examination, and genetic testing. The same variant is also noted on his father, who presents with dystrophic toenails without any blisters. This study highlights that idiopathic nail dystrophy could be linked to congenital or hereditary disease. Furthermore, we conducted a review of the literature on the characteristics of reported cases of self-improving DEB with a personal or family history of nail dystrophy. The results supported our findings that nail dystrophy may be the sole manifestation in some family members. We suggest that individuals suffering from idiopathic nail dystrophy may seek genetic counselling when planning pregnancy to early evaluate the potential risk of hereditary diseases.

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.

Immunofluorescence mapping, electron microscopy and genetics in the diagnosis and sub-classification of inherited epidermolysis bullosa: a single-centre retrospective comparative study of 87 cases with long-term follow-up

BACKGROUND

Epidermolysis bullosa (EB) comprises a heterogeneous group of skin fragility disorders, classified in four major types based on skin cleavage level, i.e. EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB), Kindler EB, and in more than 30 subtypes defined by the combination of laboratory and clinical data, including disease course.

OBJECTIVES

Our aims were to address whether, in the age of genomics, electron microscopy (TEM) has still a role in diagnosing EB, and whether the genotype per se may be sufficient to sub-classify EB.

METHODS

A thoroughly characterized single-centre EB case series was retrospectively evaluated to compare the power of TEM with immunofluorescence mapping (IFM) in establishing the EB type, and the ability of TEM, IFM and genetics to predict selected EB subtypes, i.e. severe dominant EBS (DEBS), severe JEB, severe recessive DEB (RDEB) and DEB self-improving, using genetic and final diagnosis, respectively, as gold standard.

RESULTS

The series consisted of 87 patients, including 44 newborns, with a median follow-up of 54 months. Ninety-five mutations were identified in EB-associated genes, including 25 novel variants. Both IFM and TEM were diagnostic in about all cases of JEB (21/21 for both) and DEB (43/44 for IFM, 44/44 for TEM). TEM sensitivity was superior to IFM for EBS (19/20 vs. 16/19). As to EB subtyping, IFM performed better than genetics in identifying severe JEB cases due to laminin-332 defect (14/14 vs. 10/14) and severe RDEB (eight/nine vs. seven/nine). Genetics had no role in self-improving DEB diagnosis; it almost equalled TEM in predicting severe DEBS (eight/nine vs. nine/nine) and enabled to discriminate dominant from recessive non-severe DEB phenotypes and to identify special subtypes, e.g. DEBS with KLHL24 mutations.

CONCLUSIONS

Transmission electron microscopy remains relevant to the diagnosis of EBS. IFM and genetics are essential and complementary tools in the vast majority of EB cases.

Self-improving dystrophic epidermolysis bullosa: First report of clinical, molecular, and genetic characterization of five patients from Southeast Asia

Self-improving dystrophic epidermolysis bullosa is a rare subtype of dystrophic epidermolysis bullosa (DEB) characterized by significant improvement in skin fragility within the first few years of life. Genetic inheritance has previously been reported as autosomal dominant or recessive with both forms harboring mutations in COL7A1. To date, there have been no reports of this rare clinical entity from various Southeast Asian ethnicities. Here, we describe the clinical and molecular features of five patients from the Southeast Asia region who presented with predominantly acral-distributed blisters and erosions in the first few days of life. Blistering resolved over several months, without appearance of new blisters. By immunofluorescence, intraepidermal retention of Type VII collagen was observed in all patient skin biopsies when investigated with antibody staining. Genetic analysis of four patients revealed pathogenic variants in COL7A1 which have not been previously reported. The clinical diagnosis in these rare patients is confirmed with molecular histology and genetic characterization.

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.

Intraepidermal Type VII Collagen by Immunofluorescence Mapping: A Specific Finding for Bullous Dermolysis of the Newborn

BACKGROUND

Bullous dermolysis of the newborn (BDN) is a subtype of dystrophic epidermolysis bullosa (DEB) characterized by skin fragility and blister formation at birth that typically resolves within the first year of life. Abnormal intraepidermal retention of type VII collagen (C7) has been reported as a characteristic feature of BDN, but few studies have investigated the specificity of this finding.

METHODS

We retrospectively reviewed pathology reports of patients diagnosed with DEB using immunofluorescence mapping from January 2001 to January 2015. For cases describing intraepidermal accumulation of C7, we collected information on patient characteristics, including genetic testing results, clinical outcome, and concurrent electron microscopy findings, where available.

RESULTS

Of the 143 cases of DEB with immunofluorescence mapping, eight patients had intracytoplasmic epidermal retention of C7. Of these eight patients, two were lost to follow-up, four had complete resolution of bullae, and two had marked improvement with rare residual bullae. Concurrent electron microscopic findings available for three patients were consistent with BDN.

CONCLUSIONS

Our review of immunofluorescence mapping findings in patients with DEB found that 5.6% had abnormal intracytoplasmic epidermal retention of C7, a finding previously reported in BDN. All such patients with clinical outcomes available had resolution or marked improvement of bullae, consistent with clinical outcomes expected in BDN.

Dystrophic epidermolysis bullosa: a review

Dystrophic epidermolysis bullosa is a rare inherited blistering disorder caused by mutations in the COL7A1 gene encoding type VII collagen. The deficiency and/or dysfunction of type VII collagen leads to subepidermal blistering immediately below the lamina densa, resulting in mucocutaneous fragility and disease complications such as intractable ulcers, extensive scarring, malnutrition, and malignancy. The disease is usually diagnosed by immunofluorescence mapping and/or transmission electron microscopy and subsequently subclassified into one of 14 subtypes. This review provides practical knowledge on the disease, including new therapeutic strategies.

Recessive bullous dermolysis of the newborn in preterm siblings with a missense mutation in type VII collagen

Bullous dermolysis of the newborn is a dominant or recessive inherited subtype of dystrophic epidermolysis bullosa characterized by the tendency to spontaneously stop blistering within the first months of life. Here we report two siblings with bullous dermolysis of the newborn who were born prematurely and have a novel recessive mutation, p.Pro2259Leu, in the triple helix domain of type VII collagen. We discuss the possible relationship between genotype and prematurity and clinical manifestations in these patients.

Bullous dermolysis of the newborn: four new cases and clinical review

Bullous dermolysis of the newborn (BDN) is a subtype of dystrophic epidermolysis bullosa caused by mutations in type VII collagen resulting in disorganized anchoring fibrils and sublamina densa blister formation. Disease activity is usually confined to the first year of life, with restoration of physiologic type VII collagen localization. We report four new cases of BDN and review the utility of immunofluorescence mapping in establishing the diagnosis.

Desquamative enteropathy and pyloric atresia without skin disease caused by a novel intracellular beta4 integrin mutation

BACKGROUND

Mutations in alpha6 or beta4 integrins (ITGA6, ITGB4) are known to cause junctional epidermolysis bullosa with pyloric atresia (JEB-PA), often lethal in infancy through skin desquamation. There is 1 report of pyloric atresia associated with a desquamatory enteropathy but without skin disease, of unknown molecular basis.

PATIENTS AND METHODS

We report 2 Kuwaiti siblings with pyloric atresia and life-threatening intestinal desquamation without significant skin abnormality. The older sibling died of intractable diarrhoea, and the younger sibling suffered episodes of massive protein-losing enteropathy, triggered by viral infections, in addition to obstructive uropathy. Mutation analysis was performed for ITGA6 and ITGB4 and expression of ITGA6 and ITGB4 protein was examined in skin and intestinal biopsies. Her serum also was incubated with normal intestine.

RESULTS

We identified a novel mutation in ITGB4, with homozygous deletion of a single residue (isoleucine 1314) within the intracellular plectin-binding domain. Expression of ITGA6 and ITGB4 within skin, duodenal, and colonic epithelium was normal or minimally reduced, in contrast to previous reports. Biopsies taken during relapse showed accumulation of immunoglobulin G and C1q within intestinal basement membrane, whereas immunoglobulin G from her serum bound to basement membrane of normal small intestine. Immunomodulatory therapy induced significant improvement following relapses.

CONCLUSIONS

ITGB4 mutation may induce a desquamative enteropathy in infancy without significant skin disease. A history of pyloric atresia is important in infants with severe chronic diarrhoeal disease and should prompt investigation for JEB-PA associated mutations. Acquired immune responses may exacerbate primary genetic disorders of epithelial adhesion and immunomodulatory therapy may be beneficial.

Mutation analysis and characterization of COL7A1 mutations in dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa (DEB) is inherited in both an autosomal dominant DEB and autosomal recessive manner RDEB, both of which result from mutations in the type VII collagen gene (COL7A1). To date, 324 pathogenic mutations have been detected within COL7A1 in different variants of DEB; many mutations are clustered in exon 73 (10.74%) which is close to the 39 amino acid interruption region. Dominant dystrophic epidermolysis bullosa usually involves glycine substitutions within the triple helix of COL7A1 although other missense mutations, deletions or splice-site mutations may underlie some cases. In recessive dystrophic epidermolysis bullosa, the mutations include nonsense, splice site, deletions or insertions, 'silent' glycine substitutions within the triple helix and non-glycine missense mutations within the triple helix or non-collagenous NC-2 domain. The nature of mutations in COL7A1 and their positions correlate reasonably logically with the severity of the resulting phenotypes.

Epidermolysis bullosa. II. Type VII collagen mutations and phenotype-genotype correlations in the dystrophic subtypes

BACKGROUND

The dystrophic forms of epidermolysis bullosa (DEB), a group of heritable blistering disorders, show considerable phenotypic variability, and both autosomal dominant and autosomal recessive inheritance can be recognised. DEB is derived from mutations in the type VII collagen gene (COL7A1), encoding a large collagenous protein that is the predominant, if not exclusive, component of the anchoring fibrils at the dermal-epidermal junction.

METHODS

The Dystrophic Epidermolysis Bullosa Research Association Molecular Diagnostics Laboratory (Philadelphia, Pennsylvania, USA), established in 1996, has analysed more than 1000 families with different forms of epidermolysis bullosa, among them 332 families with DEB. DNA specimens were subjected to mutation analysis by polymerase chain reaction (PCR) amplification of all 118 exons and flanking intronic sequences of COL7A1, followed either by heteroduplex scanning and sequencing of the PCR products demonstrating heteroduplexes or by direct nucleotide sequencing.

RESULTS

355 mutant alleles out of the anticipated 438 (81.1%) were disclosed. Among these mutations, a total of 242 mutations were distinct and 138 were novel, previously unreported mutations. No evidence of mutations in any other gene was obtained.

DISCUSSION

Examination of the mutation database suggested phenotype-genotype correlations, contributing to the improved subclassification of DEB with prognostic implications. The mutation information also forms the basis for accurate genetic counselling and prenatal diagnosis in families at risk for recurrence.

COL7A1 mutation G2037E causes epidermal retention of type VII collagen

COL7A1 glycine substitution (GS) mutations result in dominant and recessive dystrophic epidermolysis bullosa (DDEB and RDEB). Here, we report a DDEB family in which retention of type VII collagen by epidermal keratinocytes was observed for a female proband. Mutational analysis detected a GS mutation, G2037E, in the proband and her affected father. To demonstrate direct association of G2037E and type VII collagen retention we introduced this mutated COL7A1 gene into cultured keratinocytes using retroviral methods. This mutation was dominant, so we transferred a 1:1 mixture of wild-type (unaffected) and G2037E-mutated COL7A1, together, in addition to the unaffected gene or the mutated gene alone. The increase in type VII collagen cytoplasmic staining in the G2037E/wild transfectant cell samples was compared with that for control/wild-type cells. Intracellular collagen VII staining in the G2037E (alone)-transfected cells was even stronger than for the G2037E/wild transfection sample. These results indicate that the G2037E COL7A1 mutation leads to increased epidermal retention of type VII collagen in vivo, and also suggests that homozygotes carrying this dominant GS mutation may have more severe phenotypes than heterozygotes. This study furthers our understanding of GS COL7A1 mutations in DEB.