Idiopathic conditions have no identified cause. A substantial proportion of many diseases including certain cancers, neurological conditions, and cardiac events occur idiopathically without identifiable exposure or genetic explanation.
The idiopathic fraction varies by condition.
Alternative Names:
Idiopathic, Unknown Etiology
Why it Matters?
The idiopathic fraction is what a differential etiology must address, since an expert who excluded other identified causes has not accounted for the possibility that the condition arose without any. Where a substantial proportion of cases are idiopathic, ruling out alternatives does not establish the defendant's exposure as the cause. That argument is available whenever a plaintiff expert reasons by elimination.
Frequently Confused with
Related terms
Frequently asked questions
Why does the idiopathic fraction matter?
How does it affect differential etiology?
