<prompt> True about hyperophic scarNo genetic predispositionMore common in blood group ANo HLA associationPredominantly collagen type 4  <response>: Ans is b i.e. More common in blood group A Etiology of hyperophic scarsThey follow damage to deep dermisAutosomal dominant with incomplete inheritance.Associated with HLA B14, B21, Bw16, Bw35, DR5 DQw3.They are more common in people with A blood group. PathophysiologyHigh level of production of collagen, elastin, fibronectin, proteoglycan hyaluronic acid by fibroblast.Collagen produced is predominantly type I.There is increased level of TGE-131, P2, activin A, IFN-a y, plasminogen activator inhibitor 1PAI1 low level of urokinaseIL-6 plays a key role in keloid formation. 