Junctional epidermolysis bullosa (JEB) is an inherited form of epidermolysis bullosa characterized by involvement of the skin and mucous membranes, defined by the formation of bullous lesions between the epidermis and dermis at the level of the lucid lamina of the basal and healing lesions with atrophy and/or formation of exuberant granulation tissue.
The incidence data from US and Italian registries are 1/450,000 and 1/260,000 live births, respectively.
The JEB is an inherited disease with an autosomal recessive pattern of transmission. The JEB is caused by mutations in several genes, including COL17A1, ITGA6, ITGB4, LAMA3, LAMB3 and LAMC2.
The disease is usually present at birth, except in late-onset JEB forms.
Several JEB subtypes have been described based on clinical features. All subtypes present a hypoplasia of dental enamel that manifests as a picket of varying extent on the surface of some or all of the teeth. The formation of blisters is usually associated with atrophic scarring or the formation of exuberant granulation tissue and nail dystrophy. Other skin manifestations may also occur, such as congenital absence of skin and progressive loss of hair. The mucosal involvement is constant.
The JEB is divided into two main subtypes: the most severe Herlitz type JEB and a JEB subtype which in turn comprises six variants, of which the last three are very rare (JEB, non-Herlitz, generalized, JEB, No-Herlitz, localized, JEB with pyloric atresia, reverse JEB, late-onset JEB, LOC syndrome).
The diagnosis is based on the identification of the level in which the blisters develop in cutaneous biopsies after exerting on the skin a traction of low intensity. The different subtypes are defined based on the findings observed in immunofluorescence and electron microscopy and with the clinical presentation.
The diagnosis is usually simple and rarely a broad differential diagnosis is proposed. However, in the neonatal period, herpes simplex infection should be considered, especially if there is no family history of blistering disease, or if the clinical findings are very atypical.
Mutational DNA analysis may allow for a prenatal diagnosis.
Patients affected by most forms of JEB, as a result of the severity of skin lesions and extracutaneous manifestations and with the aim of controlling hydroelectrolytic balance, treat stunting, anemia, Infections, etc., require hospitalization in neonatal intensive care. Consequently, for the management of these patients it is necessary to have a multidisciplinary team to ensure coordinated care.