What is Junctional Epidermolysis Bullosa, LAMB3-related?
Junctional epidermolysis bullosa (JEB), LAMB3-related, caused by mutations in the LAMB3 gene, is an inherited disease that causes severe blistering of the skin. There are two types of this condition: generalized severe JEB (formerly JEB Herlitz) and generalized intermediate JEB (formerly JEB non-Herlitz).
Generalized Severe Junctional Epidermolysis Bullosa
Individuals with generalized severe JEB lack anchors to hold the layers of their skin together. They develop large, fluid-filled blisters in response to any trauma, even something as minor as increased room temperature. Internal blistering on the lining of the nose, mouth, esophagus, trachea, rectum, stomach, intestines, and eyes are also present from birth.
Granulation tissue, a kind of soft, pink, bumpy, moist skin, forms at blistering sites in the healing process. This tissue can also be seen around the nose, mouth, ears, fingers, and toes, as well as in areas that receive friction, such as the buttocks and back of the head. Because this tissue can chafe and wear away, it bleeds easily and can be a site of fluid loss, leaving the individual open to infection.
Other symptoms in infants and children with the disease may include a hoarse cry, cough, other breathing problems, fevers, loss of fingernails and toenails, poorly-formed tooth enamel, abnormalities of the urinary tract and bladder (which may lead to urinary-tract infections and kidney failure), poor growth, electrolyte imbalance, hair loss, osteoporosis, and skin cancer.
Generalized Intermediate Junctional Epidermolysis Bullosa
Generalized intermediate JEB is less severe than generalized severe JEB. Blistering occurs in fewer areas (hands, feet, knees, and elbows) and may not result in blistering of the internal organs. The onset of blistering may occur later as well. Issues related to granulation tissue and complications with breathing are not common. However, hair loss, improper nail formation, and poorly formed tooth enamel are seen.
How common is Junctional Epidermolysis Bullosa, LAMB3-related?
The incidence of JEB in the United States is approximately 1 in 275,000 to 400,000. Approximately 70% of all cases of JEB are due to mutations in the LAMB3 gene. Exact estimates of the different subtypes of JEB are not well known, although generalized intermediate JEB seems to be more common than generalized severe JEB.
How is Junctional Epidermolysis Bullosa, LAMB3-related treated?
Treatment focuses on reducing symptoms and on protecting the child as much as possible from skin damage. For example, a cesarean section may be recommended to protect the child from the skin trauma of birth. Affected children must avoid any movement or clothing that could damage the skin. To protect open wounds and blistered skin, the affected areas are covered with multiple layers of non-adhesive bandages, and anyone handling the child must use extreme care. Affected children require frequent antibiotics for infection. An expert on nutrition (dietitian) should be consulted for proper nutrition. To avoid dehydration, affected children should drink plenty of fluids. In individuals with breathing or feeding difficulty, surgical procedures to place breathing or feeding tubes may be required.
What is the prognosis for an individual with Junctional Epidermolysis Bullosa, LAMB3-related?
The prognosis for individuals with generalized severe JEB or generalized intermediate JEB is poor. The disease is extremely painful, and causes of death often include impaired physical growth (failure to thrive), infection, and respiratory failure. Most children with generalized severe JEB do not survive past the first year of life, while roughly 48% of individuals with generalized intermediate JEB die by age 15.