Basement Membrane Zone and Associated Diseases

Question 1

Epidermolysis Bullosa

Answer 1

Skin fragility with blister formation after minor trauma

• EB simplex - separates just above the BMZ
• Junctional EB - separates within the BMZ
• Dystrophic EB - separates just below the BMZ

Question 2

What connects the basement membrane to the stratum basale?

Answer 2

Hemidesmosomes. These contain plectin, a6b4 integrin, bullous pemphigoid antigen 1 (BPAg1), bullous pemphigoid antigen 2 (BPAg 2) or Type XVII collagen, laminin 332.

Question 3

EB Simplex

Answer 3

Mutations in K5 or K14 result in faulty assembly of keratin filament network

Question 4

Junctional EB

Answer 4

Varying phenotypes that range from mild blistering that improves over time to widespread splitting within the lamina lucida that results in extremely fragile skin.
- severe phenotypes are often associated with early death from infections.

Question 5

Dystrophic EB

Answer 5

• blisters that heal with extensive scarring, leading to contractures or mitten deformities of the hands
• at higher risk for squamous cell carcinomas
• due to a mutation in Type VII collagen the major component of anchoring fibrils that connect the lamina densa to the dermis. This can either be dominant or recessive.

Question 6

Bullous pemphigoid

Answer 6

• tense, intensely pruritic fluid filled vesicles located on the extremities, axillae, and groin.
• tends to occur in individuals over 60

Question 7

Pemphigoid gestationis

Answer 7

• occurs during pregnancy. Antibodies can cross the placenta and cause blisters in the newborn.
• most commonly associated with antibodies to BP180

Question 8

Mucous membrane pemphigoid

Answer 8

• lesions that primarily affect the oral cavity and conjuntivae. These tend to heal with scarring.

Question 9

Epidermolysis Bullosa Aquisita (EBA)

Answer 9

• clinically mimics dystrophic EB with blisters that heal with scarring and milia
• mediated by autoantibodies to type VII collagen

Question 10

Linear IgA Bullous Dermatosis

Answer 10

• vesiculobullous eruption in linear or arcuate patterns

- linear deposition of IgA along the BMZ