Junctional Epidermolysis Bullosa

It is an autosomal recessive disease characterized by fragility of the skin and mucous membranes, and manifests with the formation of blisters in response to minimal trauma.

Epidermolysis bullosa (EB) is a group of heterogeneous diseases associated with skin fragility, blistering, erosion and scarring of skin and mucous membranes in response to minimal mechanical trauma. It is divided into four main types, EB simplex, junctional EB, dystrophic EB and Kindler's syndrome.

Junctional epidermolysis bullosa (JEB) follows an autosomal recessive mode of inheritance and is characterized by the formation of blistering lesions between the epidermis and dermis at the level of the lamina lucida of the basement membrane. JEB is the result of alterations in up to 7 genes that code for proteins that are part of the basement membrane. Here we analyze variants in the LAMB3 gene which is the gene most frequently affected in JEB.

JEB is the rarest type of EB, with an incidence of 2.68 cases per 1,000,000 live births.

Symptoms

JEB is usually detected at birth, except in late onset forms of JEB. Up to 9 subtypes of JEB have been described based on clinical features. All of them have in common hypoplasia of tooth enamel manifesting as pitting of variable extent on the surface of some or all teeth.

Blistering is often associated with atrophic scarring (sunken scars) or abnormal growth of granulation tissue and nail dystrophy (nail deformity). Other cutaneous manifestations such as congenital absence of skin and progressive hair loss may also occur. Mucosal involvement is constant.

Blistering can be severe. Sometimes granulation tissue originates in the skin around the oral and nasal cavities, fingers and toes, and internally around the upper airway.

Disease management

Newborns affected by JEB require hospitalization in intensive care. They need special care to protect the skin and treat the lesions. In addition, water-electrolyte balance must be monitored, anemia and infections must be prevented. Abnormal granulation tissue growth is usually treated with topical steroids, silver nitrate, antibiotics and antiseptics.

Genes analyzed

LAMB3

Bibliography

Mariath LM, Santin JT, Schuler-Faccini L, Kiszewski AE. Inherited epidermolysis bullosa: update on the clinical and genetic aspects. An Bras Dermatol. 2020 Sep-Oct;95(5):551-569.

Pfendner EG, Lucky AW. Junctional Epidermolysis Bullosa. 2008 Feb 22 [updated 2018 Dec 20]. In: Adam MP, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2022.

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