12-year old patient presented with this type of scaling [scales, large “plate-like” , very thick, dark brown and firmly adherent, have been over most of the skin surface including the face (A and B) and accentuated on lower extremities (C)] which started within the first month of life. Which congenital disorder of cornification is this?
Normally, cornification involves the construction of the cornified envelope from intracellular protein precursors including loricrin and involucrin. These are cross-linked to lipid ceramides in the granular layer by the action of transglutaminase 1. retention hyperkeratosis with hypergranulosis)
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