This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Angioedema is seen due to deficiency of? \nSelect and explain. \nA. Angiotensin converting enzyme, B. C1 esterase inhibitor, C. Histamine, D. Angiotensin 1', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Angioedema (angioedema/ Quincke’s edema/ angioneurotic edema) \n\nCharacterized by rapid swelling (edema) of the dermis,\xa0subcutaneous tissue, mucosa and submucosal tissues. It is very similar to urticaria, but urticaria, commonly known as hives,\xa0occurs in the upper dermis\nAngioedema is classified as either hereditary or acquired.\n\na) Acquired angioedema (AAE) can be immunologic, nonimmunologic, or idiopathic.\nIt is usually caused by allergy and occurs together with other allergic symptoms and urticaria.\nIt can also occur as a side effect of certain medications,\xa0particularly ACE inhibitors.\nb) Hereditary angioedema (HAE) exists in three forms, all of which are caused by a genetic mutation inherited in an autosomal dominant form.\ni) Types I and II are caused by mutations in the SERPINGl gene,\xa0which result in either diminished levels of the C1-esterase inhibitor protein (type I HAE) or dysfunctional forms of the same protein (type II HAE).\nii) Type III HAE has been linked with mutations in the F12 gene, which encodes the coagulation protein factor, XII.\n\nAll forms of HAE lead to abnormal activation of the complement system.\nThe end product of this cascade, bradykinin,\xa0is produced in large amounts and is believed to be the predominant mediator leading to increased vascular permeability and vasodilation that induces typical angioedema "attacks".', 'role': 'assistant'}]