Neurofibromatosis type I (NF-1), formerly known as von Recklinghausen disease after the researcher (Friedrich Daniel von Recklinghausen) who first documented the disorder, is a human genetic disorder. It is possibly the most common inherited disorder caused by a single gene. NF-1 is not to be confused with Proteus Syndrome (the syndrome which may have affected The Elephant Man), but rather is a separate disorder. In diagnosis it may also be confused with Legius syndrome.