Clinical phenotype of Bart's syndrome seen in a family with dominant dystrophic epidermolysis bullosa

Epidermolysis bullosa with congenital absence of skin: Review of the literature

BACKGROUND/OBJECTIVES

Bart syndrome was initially described as association of congenital absence of skin (CAS), nail abnormalities, and epidermolysis bullosa (EB). Further reports of patients with CAS and EB have been made with wide clinical heterogeneity among them. Current guidelines recommend the elimination of eponyms and use of the descriptive term EB with CAS.

METHODS

We performed a PubMed and Medline database search of patients with Bart syndrome or EB with CAS. We included case reports or case series that contained clinical and demographic information.

RESULTS

After review, 55 articles were included, reporting 96 patients. CAS involved the lower extremities in all patients, with additional upper limb, trunk, or head involvement in 17%. In all patients, the time to healing ranged from 2 weeks to 6 months; most received only conservative treatment. The subtype and frequency of associated EB most frequently reported were recessive dystrophic EB (41.4%) and dominant dystrophic EB (22.8%). Extracutaneous features were present in 29 patients; with pyloric atresia and ear malformations being the most common. The prognosis varied based on the subtype of EB and the presence of additional comorbidities; 50% of the patients with junctional EB with pyloric atresia and CAS died during the first months of life, while mortality among those with recessive dystrophic EB was 6.8%.

CONCLUSION

Epidermolysis bullosa with CAS is a clinically heterogeneous disorder, most often associated with recessive dystrophic EB, but other EB subtypes may occur. Further investigations are necessary to better establish a pathological mechanism for CAS, and its association with EB.

[Bart syndrome associated to lethal junctional epidermolysis bullosa (Herlitz form)]

We present the case of a newborn with congenital absence of skin in the anterior part of the left leg that shortly after developed bulla and erosions in hands, feet, ears, buttocks and mouth. The cutaneous biopsy and ultrastructural and immunohistochemical studies showed a subepidermal bulla in the lamina lucida, absence of hemidesmosomes and marked decrease of laminin 5, thus establishing the diagnosis of Bart syndrome associated to the Herlitz form of lethal junctional epidermolysis bullosa. Bart syndrome consists of congenital and localized absence of skin, nail abnormalities and mucoc-cutaneous bullae. It is usually associated to dystrophic epidermolysis bullosa. The Herlitz form of junctional epidermolysis bullosa is a rare variant, usually lethal that is produced by mutations in the genes coding for the anchor protein laminin 5. To our knowledge this is the second case that reports an association between Bart syndrome and lethal junctional epidermolysis bullosa and the first in which the results of immunofluorescence mapping are published.

Genetic abnormalities and clinical classification of epidermolysis bullosa

Genetic abnormalities for different subtypes of epidermolysis bullosa (EB) have been described. In dominant simplex type EB, mutations of the K5 or K14 gene lead to disruption of basal cells and the formation of bullae. The recessive simplex types include EB with muscular dystrophy due to abnormal plectin, EB without muscular dystrophy in patients homozygous for K14 gene abnormalities, and skin fragility syndrome, with formation of acantholytic vesicles within the epidermis due to PKP1 gene mutations. In junctional EB, mutations of the laminin 5, type XVII collagen, and alpha 6 beta 4 integrin genes have been reported. Dystrophic type EB is associated with various abnormalities of the type VII collagen gene. A new classification of EB based on these genetic abnormalities has been proposed. However, some concern has been voiced regarding the clinical utility of a classification based solely on genetic abnormalities. Although the reasons are unclear, identical genetic abnormalities have been known to be associated with different clinical features. A classification including a component based on clinical features would therefore be preferable. This article describes recently discovered genetic abnormalities and offers a new classification scheme for EB.