Prenatal diagnosis of Herlitz junctional epidermolysis bullosa by amniocentesis

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.

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.

Laminin-10 is crucial for hair morphogenesis

The role of the extracellular matrix in cutaneous morphogenesis is poorly understood. Here, we describe the essential role of laminin-10 (alpha5beta1gamma1) in hair follicle development. Laminin-10 was present in the basement membrane of elongating hair germs, when other laminins were downregulated, suggesting a role for laminin-10 in hair development. Treatment of human scalp xenografts with antibodies to laminin-10, or its receptor beta1 integrin, produced alopecia. E16.5 Lama5 -/- mouse skin, lacking laminin-10, contained fewer hair germs compared with controls, and after transplantation, Lama5 -/- skin showed a failure of hair germ elongation followed by complete hair follicle regression. Lama5 -/- skin showed defective basement membrane assembly, without measurable increases in anoikis. Instead, Lama5 -/- skin showed decreased expression of early hair markers including sonic hedgehog and Gli1, implicating laminin-10 in developmental signaling. Intriguingly, treatment of Lama5 -/- skin with purified laminin-10 corrected basement membrane defects and restored hair follicle development. We conclude that laminin-10 is required for hair follicle development and report the first use of exogenous protein to correct a cutaneous developmental defect.

Genetic reversion of inherited skin disorders

Human epidermis is a squamous stratified epithelium whose integrity relies on balanced processes of cell attachment, proliferation, and differentiation. In monogenic skin dermatoses, such as mecano-bullous diseases, or DNA repair deficiencies such as the xeroderma pigmentosum (XP), alterations of skin integrity may have devastating consequences as illustrated by the extremely high epidermal cancer proneness of XP patients. The lack of efficient pharmacological treatments, the easy accessibility of skin, and the possibility of long term culture and genetic manipulations ex vivo of epidermal keratinocytes, have encouraged approaches toward gene transfer and skin therapy prospects. We review here some of the human genetic disorders that exhibit major traits in skin, as well as requirements and difficulties inherent to approaches aimed at stable phenotypic correction.

Junctional epidermolysis bullosa gravis (Herlitz): diagnostic and genetic aspects

We report on a boy suffering from lethal junctional epidermolysis bullosa gravis (JEBH) (Herlitz-type) (OMIM 226700). Screening for mutations of LAMB3 gene with polymerase chain reaction (PCR) amplification of all exons from genomic DNA and subsequent heteroduplex analysis and dideoxynucleotide sequencing of heteroduplex forming PCR products disclosed two mutations: the recurrent maternal mutation R635X and the novel paternal mutation 1629insG, both in exon 14 of LAMB3. Both mutations lead to a premature termination code, non-sense mediated mRNA decay and to absence of the synthesis of the beta3 chain of laminin 5. During the mutation screening of the index patient a second pregnancy was ascertained. After amniocentesis (14 + 1 week of pregnancy), prenatal diagnosis from fetal cells was performed and compound heterozygosity for both mutations was evident. The consultants decided to have a termination of pregnancy shortly after the diagnosis. Remarkable skin fragility of the fetus was evident by clinical examination. Complete absence of laminin 5 could be demonstrated by immunofluorescence staining. By the third pregnancy of this couple so far screened for mutations by chorionic villus sampling for prenatal molecular diagnosis a healthy but heterozygous child is expected.

Laminins and human disease

The laminin protein family has diverse tissue expression patterns and is involved in the pathology of a number of organs, including skin, muscle, and nerve. In the skin, laminins 5 and 6 contribute to dermal-epidermal cohesion, and mutations in the constituent chains result in the blistering phenotype observed in patients with junctional epidermolysis bullosa (JEB). Allelic heterogeneity is observed in patients with JEB: mutations that results in premature stop codons produce a more severe phenotype than do missense mutations. Gene therapy approaches are currently being studied in the treatment of this disease. A blistering phenotype is also observed in patients with acquired cicatricial pemphigoid (CP). Autoantibodies targeted against laminins 5 and 6 destabilize epithelial adhesion and are pathogenic. In muscle cells, laminin alpha 2 is a component of the bridge that links the actin cytoskeleton to the extracellular matrix. In patients with laminin alpha 2 mutations, the bridge is disrupted and mature muscle cells apoptose. Congenital muscular dystrophy (CMD) results. The role of laminin in diseases of the nervous system is less well defined, but the extracellular protein has been shown to serve an important role in peripheral nerve regeneration. The adhesive molecule influences neurite outgrowth, neural differentiation, and synapse formation. The broad spatial distribution of laminin gene products suggests that laminin may be involved in a number of diseases for which pathogenic mechanisms are still being unraveled.