Form Of Recessive Dystrophic Epidermolysis Bullosa Research Articles

Molecular profiling of an Indian EB cohort - a single centre experience.

Epidermolysis bullosa (EB) encompasses rare hereditary skin conditions marked by skin fragility, nail dystrophy, and minor trauma-induced skin blisters. This study aims to identify genetic variants in Indian EB patients and examine the relationship between genotypic and phenotypic manifestations. EB patients seen consecutively over a period of 5 years at Outpatient Department of Dermatology. Baseline demographic data, birth history, family history, skin manifestation at birth, past medical history, current cutaneous manifestations, and the evolution of the disease were assessed and recorded. Genetic variants were identified using targeted gene panel sequencing of 23 EB-related genes, and a genetic-phenotype analysis was performed. Our study included 65 patients with EB. Among 65 EB patients, 38 dystrophic EB cases (58.46%), 12 junctional EB (18.46%), 12 epidermolysis bullosa simplex (18.46%), and 3 Kindler EB (4.62%) were reported. Dominant and recessive forms of dystrophic EB accounted for 16.92% and 41.4%, respectively. We identified 75 unique genetic variants, 58.67% newly discovered and 41.33% previously reported. Compound heterozygous variations were more frequent (55.55%) than homozygous ones (44.44%) in recessive dystrophic EB patients. Junctional EB patients harboured LAMB3 gene mutations more frequently, while epidermolysis bullosa simplex patients showed KRT5 and KRT14 gene missense heterozygous mutations. Kindler EB patients had homozygous mutations in the FERTM1 gene. Our study unveiled several novel genetic variants; severe phenotypes associated with nonsense genetic variants. These findings offer valuable insights for future clinical assessments and tailored management strategies.

The clinical spectrum of dystrophic epidermolysis bullosa.

Dystrophic epidermolysis bullosa (DEB) is a genodermatosis resulting from mutations in COL7A1, the gene encoding type VII collagen. The site and specific nature of the underlying mutation determine the clinical phenotype, which ranges widely from a severe mutilating condition to a relatively mild disorder. To document the clinical spectrum of DEB within a defined complete population. Since 1992, when compilation of the U.K. epidermolysis bullosa register began, an exhaustive search for DEB sufferers within the Scottish population has been undertaken and their clinical features comprehensively recorded. One hundred and twenty-eight DEB sufferers have been identified within the Scottish population. In descending order, the frequencies of the different forms of DEB were dominant DEB (DDEB) in 88 individuals (68%), DEB of uncertain inheritance in 24 (19%) and recessive DEB (RDEB) in 16 patients (13%). Within this latter group, nine (7%) had the mutilating Hallopeau-Siemens subtype (RDEB-HS), five (4%) had localized (RDEB-loc) and two (2%) had a predominantly flexural (inverse) form of RDEB. During the study, two patients with RDEB died from squamous cell carcinomas (SCCs), one originating in the skin and the second arising in the oesophagus. Gastrointestinal problems such as dysphagia, constipation and anal fissures, and restriction of mouth opening were experienced by the majority of patients with RDEB and by a significant minority of DDEB sufferers. Pseudosyndactyly was most severe in RDEB-HS, all those over 9 years of age having mitten deformities of the hands. Milder pseudosyndactyly or flexion contractures of the fingers were present in younger patients with this subtype, in most adults suffering from other subtypes of RDEB and in 6% of those with DDEB. External ear involvement, a feature not often reported in DEB, was common in RDEB and also occurred in a minority of those with DDEB. Pruriginous lesions and albopapuloid lesions were each present in both DDEB and RDEB. Most patients with DEB have relatively mild dominantly inherited disease, only a minority suffering from severe recessive subtypes. Scarring, gastrointestinal involvement, albopapuloid lesions and a pruriginosa-like pattern each occur in both DDEB and RDEB. With increasing age, SCC is a major cause of morbidity and mortality.

Characterization of mutations of the type VII collagen gene (COL7A1) in recessive dystrophic epidermolysis bullosa mitis (M-RDEB) from three Korean patients

In recent years, the molecular basis for the main subtypes of epidermolysis bullosa (EB) has been elucidated with pathogenetic mutations delineated in ten different genes encoding structural components of the dermal–epidermal junction. Both the autosomal dominant and recessive forms of dystrophic EB (DEB) is caused by mutations in the COL7A1 gene. Type VII collagen is a major component of anchoring fibrils, structural elements that stabilize the attachment of the basement membrane to underlying dermis. Recent delineation of the exon–intron organization of the COL7A1 gene provided the basis for the comprehensive design of PCR primer pairs that amplified exons in genomic DNA by placing the primers on the flanking introns. A number of COL7A1 mutations have been reported and some genotype–phenotype correlations are starting to emerge. In this study, we examined mutational analyses from three Korean patients with recessive dystrophic EB (RDEB) mitis. We designed and optimized primers according to the previously reported sequences. Such PCR amplification products can be examined by electrophoretic scanning technique, CSGE heteroduplex analyses. Utilizing heteroduplex analyses, we have identified a number of sequence variants in COL7A1 both in unaffected individuals and in patients with M-RDEB. Mutation detection of the COL7A1 gene revealed six allelic mutations (V6677E, P6685S, Y3749S, P6084S, P6695R and G6697C). We suggest that the full length of type VII collagen polypeptide are synthesized, but those missense mutations, that may affect a critical amino acid, can alter the conformation of the protein and interferes with the assembly and packing of type VII collagen molecules into anchoring fibrils. Immunohistochemical study of skin biopsies by use of anti-type VII collagen antibody showed markedly reduced staining and presence of a dermo/epidermal cleavage. This is the first report of a COL7A1 mutation study in DEB from Korean patients. We hope that these data contribute to the expanding database on COL7A1 mutations in dystrophic epidermolysis bullosa, and further illustrate the extensive diversity of mutational events that led to the RDEB phenotype.

Prenatal Diagnosis for Recessive Dystrophic Epidermolysis Bullosa in 10 Families by Mutation and Haplotype Analysis in the Type VII Collagen Gene (COL7A1)

Epidermolysis bullosa (EB) is a group of heritable diseases that manifest as blistering and erosions of the skin and mucous membranes. In the dystrophic forms of EB (DEB), the diagnostic hallmark is abnormalities in the anchoring fibrils, attachment structures beneath the cutaneous basement membrane zone. The major component of anchoring fibrils is type VII collagen, and DEB has been linked to the type VII collagen gene (COL7A1) at 3p21, with no evidence for locus heterogeneity. Due to life-threatening complications and significant long-term morbidity associated with the severe, mutilating form of recessive dystrophic EB (RDEB), there has been a demand for prenatal diagnosis from families with affected offspring.Intragenic polymorphisms in COL7A1 and flanking microsatellite markers on chromosome 3p21, as well as detection of pathogenetic mutations in families, were used to perform PCR-based prenatal diagnosis from DNA obtained by chorionic villus sampling at 10-15 weeks or amniocentesis at 12-15 weeks gestation in 10 families at risk for recurrence of RDEB.In nine cases, the fetus was predicted to be normal or a clinically unaffected carrier of a mutation in one allele. These predictions have been validated in nine cases by the birth of a healthy child. In one case, an affected fetus was predicted, and the diagnosis was confirmed by fetal skin biopsy.DNA-based prenatal diagnosis of RDEB offers an early, expedient method of testing which will largely replace the previously available invasive fetal skin biopsy at 18-20 weeks gestation.

Dominant dystrophic epidermolysis bullosa: identification of a Gly-->Ser substitution in the triple-helical domain of type VII collagen.

Epidermolysis bullosa (EB) represents a group of genodermatoses characterized by fragility and easy blistering of the skin. In the dystrophic forms of EB, blisters occur below the basement membrane of the skin, at the level of the anchoring fibrils. We have recently demonstrated tight genetic linkage between the type VII collagen gene (COL7A1) and both the dominant and recessive forms of dystrophic EB. We searched for mutations in dominant dystrophic EB by PCR amplification of genomic segments of COL7A1, followed by heteroduplex analysis. Examination of the PCR fragment corresponding to exon 73 of COL7A1 revealed a marked shift in the electrophoretic pattern in patients from a large Finnish dominant dystrophic EB family with genetic linkage to the COL7A1 locus (Z = 5.37, theta = 0). Sequence analysis revealed a G-->A transition at nucleotide 6118 in the triple helical domain of COL7A1, which converted a glycine residue to a serine (GGT-->AGT). This mutation occurs between interruptions 11 and 12 of the triple helix, in the seventh of a series of 24 uninterrupted Gly-Xaa-Yaa repeats. Pathogenetic glycine substitutions that disrupt the triple helix have been shown to exert a deleterious effect on the protein in several other disorders involving collagen genes. The clinical phenotype in this family probably arises due to a dominant negative mutation in type VII collagen, resulting in the formation of structurally abnormal anchoring fibrils.