Immunofluorescence Analysis of Villous Trophoblasts: A Tool for Prenatal Diagnosis of Inherited Epidermolysis Bullosa with Pyloric Atresia

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.

Retrospective evidence on outcomes and experiences of pregnancy and childbirth in epidermolysis bullosa in Australia and New Zealand

BACKGROUND

Pregnancy in epidermolysis bullosa (EB) has not been comprehensively studied.

OBJECTIVE

We aimed to develop a foundational database, which could provide peri-obstetric advice in EB.

METHODS

Survey questionnaires were sent to obstetricians, unaffected mothers of EB babies, and mothers with EB. Results were analyzed using chi-square, Fisher exact, and t-tests.

RESULTS

Out of 1346 obstetricians surveyed, 195 responded, and only 14 had encountered EB. All recommended normal vaginal delivery (NVD), except for one elective Caesarean section (CS). We received responses from 75 unaffected mothers who had delivered EB babies. They had significantly more complications in their EB pregnancies compared to their non-EB pregnancies. A further 44 women with various types of EB who had given birth responded. Most delivered via NVD and had no significant increase in complications in both their EB and non-EB pregnancies. In both groups, there were no significant differences in blistering at birth in babies delivered via NVD and CS.

CONCLUSION

In conclusion, most patients with EB who are capable of giving birth do not have an increased risk for pregnancy-related complications and NVD appears to be safe. Awareness of this data amongst obstetricians and dermatologists should lead to improved quality of care for mothers and babies affected with EB.

Compound heterozygosity for novel splice site mutations of ITGA6 in lethal junctional epidermolysis bullosa with pyloric atresia

Junctional epidermolysis bullosa with pyloric atresia (PA-JEB) is a rare congenital bullous disease with gastrointestinal disturbance that has been associated with mutations in ITGA6 or ITGB4 encoding the α6 or β4 subunit of integrin, respectively. Only six ITGA6 mutations in PA-JEB have been reported while many ITGB4 mutations have been identified, and all the ITGA6 mutations were homozygous. Here, we report a case of lethal type PA-JEB, in which immunofluorescence showed the lack of both α6 and β4 integrins resulting from compound heterozygous splice site mutation in ITGA6, c.387G>T and c.2506-1G>C. Maternal c.387G>T induced the skipping of the entire exon 3 and both exons 3 and 4, resulting in premature termination codon and in-frame deletion, respectively. Paternal c.2506-1G>C caused the skipping of the exon 20 and resulted in in-frame deletion. As a reason why the present case showed lethal phenotype despite the in-frame deletion mutation, rapid degradation of neo-synthesized α6 protein and/or impaired transport of integrin were suggested from previous reports, and the lack of localization of integrin α6β4 to the epidermal basement membrane resulted in skin fragility. Our case expands the variety of integrin α6 mutations in PA-JEB.

Retrospective evidence on outcomes and experiences of pregnancy and childbirth in epidermolysis bullosa in Australia and New Zealand

Background

Pregnancy in epidermolysis bullosa (EB) has not been comprehensively studied.

Objective

We aimed to develop a foundational database, which could provide peri-obstetric advice in EB.

Methods

Survey questionnaires were sent to obstetricians, unaffected mothers of EB babies, and mothers with EB. Results were analyzed using chi-square, Fisher exact, and t-tests.

Results

Out of 1346 obstetricians surveyed, 195 responded, and only 14 had encountered EB. All recommended normal vaginal delivery (NVD), except for one elective Caesarean section (CS). We received responses from 75 unaffected mothers who had delivered EB babies. They had significantly more complications in their EB pregnancies compared to their non-EB pregnancies. A further 44 women with various types of EB who had given birth responded. Most delivered via NVD and had no significant increase in complications in both their EB and non-EB pregnancies. In both groups, there were no significant differences in blistering at birth in babies delivered via NVD and CS.

Conclusion

In conclusion, most patients with EB who are capable of giving birth do not have an increased risk for pregnancy-related complications and NVD appears to be safe. Awareness of this data amongst obstetricians and dermatologists should lead to improved quality of care for mothers and babies affected with EB.

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There is limited information on pregnancy in EB.

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This is the first comprehensive study in the world on pregnancy experiences of a large group of mothers with EB, unaffected mothers of EB babies and an obstetrician survey.

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We have recommendations for mothers expecting EB babies and expectant mothers with EB.

Molecular organization of the basement membrane zone

The dermal-epidermal basement membrane is a complex assembly of proteins that provide adhesion and regulate many important processes such as development, wound healing, and cancer progression. This contribution focuses on the structure and function of individual components of the basement membrane, how they assemble together, and how they participate in human tissues and diseases, with an emphasis on skin involvement. Understanding the composition and structure of the basement membrane provides insight into the pathophysiology of inherited blistering disorders, such as epidermolysis bullosa, and acquired bullous diseases, such as the pemphigoid group of autoimmune diseases and epidermolysis bullosa acquisita.

Role of dermal-epidermal basement membrane zone in skin, cancer, and developmental disorders

The dermal-epidermal basement membrane zone is an important epithelial and stromal interface, consisting of an intricately organized collection of intracellular, transmembrane, and extracellular matrix proteins. The basement membrane zone has several main functions including acting as a permeability barrier, forming an adhesive interface between epithelial cells and the underlying matrix, and controlling cellular organization and differentiation. This article identifies key molecular players of the dermal-epidermal membrane zone, and highlights recent research studies that have identified structural and functional roles of these components in the context of various blistering, neoplastic, and developmental syndromes.

Epidermolysis bullosa with pyloric atresia

Epidermolysis bullosa (EB) with pyloric atresia (PA) is a rare form of EB. This article describes the clinical and pathologic features and molecular genetics of EB-PA, the mutations in the alpha(6)beta(4) integrin and plectin genes that cause EB-PA, and the clinical implications of molecular genetics on EB-PA.

Place of human amniotic membrane immunoblotting in the diagnosis of autoimmune bullous dermatoses

BACKGROUND

Fine analysis of antiskin autoantibodies can contribute to the differential diagnosis of autoimmune bullous dermatoses.

OBJECTIVES

To develop a high-performance immunoblotting method using human amniotic membrane as the antigen source, and to compare it with current laboratory methods.

METHODS

Sera from 113 patients were tested by immunoblotting (IB), rat and monkey oesophagus and salt-split skin indirect immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA) quantification of anti-BP180-NC16a and anti-BP230, or antidesmoglein (Dsg) 1 and 3 antibodies. There were 56 cases of bullous pemphigoid (BP), 22 cases of mucous membrane pemphigoid (MMP), eight cases of epidermolysis bullosa acquisita (EBA), two cases of bullous systemic lupus erythematosus (BSLE), 17 cases of pemphigus vulgaris (PV), and four cases each of pemphigus foliaceus (PF) and paraneoplastic pemphigus (PNP).

RESULTS

In BP, the three methods had similar sensitivity (84-89%) for both anti-BP180-NC16a and anti-BP230 antibody detection. In MMP, autoantibodies (mainly directed against BP180 or laminin 332 subunits) were detected in 77% of patients by IB, compared with only 9% by IIF on rat and monkey oesophagus and 36% on salt-split skin, and 14% by anti-BP180-NC16a and anti-BP230 ELISA. In patients with pemphigus, ELISA had 92% sensitivity for anti-Dsg1 and 3, but IB and rat bladder IIF were necessary to confirm PNP by revealing specific and rare patterns (antidesmoplakin I/II, antienvoplakin and antiperiplakin antibodies). IB also revealed anticollagen VII antibodies in 60% of patients with EBA and BSLE, and antibodies to BP180, BP230 and Dsg3 in a few patients who were negative using the other two techniques.

CONCLUSION

Amniotic membrane immunoblotting is an interesting diagnostic tool for bullous diseases, as the entire panel of autoantibodies can be detected with a single extract. This method improves the identification of complex and heterogeneous autoimmune processes in conjunction with IIF and ELISA, and is particularly useful for MMP characterization.