Isherwood syndrome is a chronic, congenital disease present in approximately five per cent of the Sivadian population. Its main symptom is joint pains. It is similar in some ways to arthritis, though patients suffer from the joint pains all through life rather than developing them over time.
The syndrome is named after the first king of Sivad, King Franklin I, one of the disease's most prominent sufferers. It is believed to have started as a genetic mutation caused by radiation poisoning during the occupation of Sivad by the Kretonians.
Attempts to alleviate Isherwood syndrome through genetic therapy have so far failed, but the pain is easily managed through any one of an assortment of drugs, including Regisan. After many years of unsuccessful research, the program to find a genetic cure for Isherwood syndrome was cut in 3001 by the Department of Health.
Because it is easily treated, Isherwood syndrome is not considered a serious illness on Sivad today. The treatment of Isherwood syndrome is completely covered by Sivad's National Health System.