Huntington's disease is the best known example. Its pathogenic gene was discovered in 1984, but medical science still has no treatment for this disease. All patients can do after the disease is identified in a screening test is to wait for it to manifest itself.
亨丁頓舞蹈症就是最著名的例子，它的致病基因在一九八四年就已發現，但二十年後的今天，醫界還是束手無策，只能篩檢後卻坐待它發生。