Chapter 33 - Epidermolysis Bullosa Flashcards
What are the three main types of inherited epidermolysis bullosa (EB)?
Simplex, junctional, and dystrophic
True or false: any epithelial-lined organ is at risk of involvement in the severe forms of inherited EB.
True
How are most forms of EB simplex inherited?
Autosomal dominant inheritance
Which two molecules are most commonly involved in the various types of EB simplex?
Keratin 5 and 14
Mutations in either K5 or K14 are typically involved in EB simplex, however EB simplex with muscular dystrophy is an exception. Which protein is affected in this form of EB simplex?
Plectin
How is junctional EB inherited? What is the exception?
Autosomal recessive inheritance; there is no exception (they’re all AR)
What protein is mutated in the most severe form of junctional EB, Herlitz subtype?
Laminin 332
What are the two possible proteins that can be mutated in JEB-non-Herlitz type?
Laminin 332 and BP2
What are the three major eponymously named subtypes of EB simplex?
Weber-Cockayne EB simplex, Koebner EB simplex, and Dowling-Meara EB simplex
Where do blisters form in the simplex types of EB?
Within the basal keratinocyte layer
True or false: hemidesmosomes are absent in the Herlitz type of junctional EB.
True
True or false: hemidesmosomes are absent in the non-Herlitz type of junctional EB.
False; however they are reduced in number and rudimentary in appearance
True of false: anchoring fibrils appear rudimentary in dominant dystrophic EB.
False; they appear normal in size in structure (although they are, of course, functionally abnormal)
True or false: anchoring fibrils are completely absent in the Hallopeau-Siemens subtype of recessive dystrophic EB.
True
True or false: in the non-Hallopeau-Siemens subtypes of recessive dystrophic EB the anchoring fibrils are drastically reduced in number, and if present, appear rudimentary.
True
What two proteins could be mutated in JEB-non-Herlitz type EB?
Laminin 332 or BP2
True or false: BP2 and collagen VXII are the same molecule.
True
What protein is mutated in JEB with pyloric atresia?
Either of the genes that code for alpha6-beta4
True or false: dystrophic EB can be inherited in either an AR or AD way.
True
True or false: patients with recessive dystrophic EB have an increased risk of BCC.
False; they have an increased risk of SCC