With some other medical conditions, the root cause for a large percentage of all cases has not been established—for example, focal segmental glomerulosclerosis or ankylosing spondylitis; the majority of these cases are deemed idiopathic.
[2] Certain medical conditions, when idiopathic, notably some forms of epilepsy and stroke, are preferentially described by the synonymous term of cryptogenic.
[3][4] The term 'idiopathic' derives from Greek ἴδιος idios "one's own" and πάθος pathos "suffering", so idiopathy means approximately "a disease of its own kind".
Environmental and occupational risk factors are increasingly being associated with diseases classified as idiopathic.
[3] The use of cryptogenic is also sometimes reserved for cases where it is presumed that the cause is simple and will be found in the future.