<prompt> A 60 yr old lady is concerned about the wrinkles around her eyes.This is due to defect inCollagenaseDesmosineFibrillincollagen cross linking  <response>: Collagen cross-linking: Cross linking occurs when a protein linked to other protein,lipid or sugar which is necessary for normal collagen function. Abnormal cross linking causes wrinklesages skin which is due to glucose mediated advance glycation end productsAGE,UV mediated free radical damage. Collagenase: Defect in collagen leads to increased level of collagen Collagenase inhibitor are given to treat wrinkles Desmosine: Desmosine is formed by 3allsyl side chains and one unaltered lysyl side chain of elastin. Fibrillin: It is a glycoprotein secreted by fibroblasts. It forms a framework of elastin deposition Defect in fibrillin-1 results in Marfans syndrome Reference: Harpers illustrated biochemistry 30th edition 