Junctional Epidermolysis Bullosa (LAMB3-Related) (LAMB3)
Junctional epidermolysis bullosa (LAMB3-Related) is an autosomal recessive, pan-ethnic disease that is caused by pathogenic variants in the LAMB3 gene. This disease can be divided into two forms, known as the Herlitz and non-Herlitz types. The Herlitz type is more severe and is lethal in infancy. Clinical features of both types include fragile skin and mucous membranes that are prone to blistering. In the Herlitz types, blisters may be present at birth and can lead to frequent infections, electrolyte imbalances, and blood loss. Blisters also occur in the mouth and airway, eyes and bladder. Recurrent cycles of blistering and healing leads to narrowing of the airway, which may be fatal. In the non-Herlitz type, blistering is milder and may be localized to certain parts of the body. Some patients do not experience blistering after the newborn period. Some patients may have areas without skin and abnormalities of the nails and hair. Life expectancy is in the first year for infants with Herlitz junctional epidermolysis bullosa, but is usually normal in patients with the non-Herlitz type. The presence of two null variants is associated with development of Herlitz junctional epidermolysis bullosa.
For information about carrier frequency and residual risk, please see the residual risk table.