Junctional EB in Depth

Junctional Epidermolysis Bullosa is an autosomal recessive disorder.  The most prominent characteristic is the lack of tooth enamel which effects all sub-types of Junctional EB.

There are two main sub-types of Junctional EB (JEB)- generalized and localized.

 

Generalized

Generalized Severe JEB (JEB-sev gen)- the protein affected is the Laminin 332 protein

Common Features: the appearance of symmetrical granulation tissue around the mouth and nose is a significant, as is non healing wounds on the back of the head, the bottom  and upper part of the back.  The eyes, upper respiratory tract and genitals are also affected.  Anemia, malnutrition, dehydration and airway obstruction are common and the leading cause of death for this subtype. 

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Generalized Intermediate JEB (JEB- gen intermed)- the proteins affected are Laminin 332 and Collagen 17

Common Features: Blistering or massive skin loss present at birth; generalized blistering, dysphoric or absent nails, and post-inflammatory hypo-pigmentation is common throughout life.  Alopecia is also common.  There is a lower risk of death due to anemia, malnutrition and airway occlusion, but it can occur in some patients.  There have been some cases of squamous cell carcinoma reported in patients with this type.

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Junctional EB with pyloric atresia (JEB-PA)- the protein affected is alpha6Beta4 Integrin 

Common Features: generalized blistering present at birth along with pyloric atresia.  Congenital abnormalities of the genitourinary tract may also be present and severity can range from mild to fatal.

 

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Localized

Localized JEB( JEB-loc)- the proteins affected are Laminin 332, Collagen 17 and Beta4 Integrin

Common Features: blisters usually confined to the hands, feet and lower leg; nails are usually absent or dystrophic and dental abnormalities are common

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JEB Inversa (JEB-inv)- the protein affected is Laminin 332

Common Features:  this rare type of JEB is characterized by blisters, erosions and slow healing wounds  only on the intertriginous skin sites (the folds and bends of the body), the esophagus, and vagina.

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LOC Syndrome- the protein affected is the Alpha 3 chain of the Laminin 332 gene.

Common Features: formation of blisters on the face and neck along with the formation of granulation tissue; tooth, eye and upper airway abnormalities

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