idiogenesis

Origin without evident cause; denoting especially that of an idiopathic disease. [idio- + G. genesis, production]

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id·io·gen·e·sis .id-ē-ə-'jen-ə-səs n, pl -e·ses -.sēz spontaneous origin (as of disease)

idio·ge·net·ic -jə-'net-ik adj

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id·io·gen·e·sis (id″e-o-jenґə-sis) [idio- + -genesis] the origin of disease without a known cause, as in an idiopathic disease.