WASHINGTON -- A medical mystery is still unfolding at the White House.
President Bush, like his wife, Barbara, has received a diagnosis of Graves' disease, an autoimmune ailment of unknown cause. It is rare enough for a husband and wife to contract the disease, which is not known to be communicable. Even more odd is that Millie, the Bushes' dog, also has an autoimmune disease, lupus.
The president's disease was diagnosed this month, the first lady's in January 1990, and Millie's last summer. In 16 months, three members of the Bush household have contracted a disease in which the immune system, for unknown reasons, interferes with the body's own tissues.
The cluster of cases may be pure coincidence. But could whatever caused Millie's lupus also have induced the Graves' disease that has afflicted Mr. Bush and his wife? That is a possibility that has intrigued medical experts around the country, and it is now being considered by the president's physician, Dr. Burton J. Lee III.
Scientists have long suspected that microbes or other environmental factors might set off autoimmune disorders like lupus and Graves' disease among the individuals, human or animal, who are genetically susceptible. Among the current suspects are a bacterium known as Yersinia enterocolitica and entities known as retroviruses, but nothing has been proved regarding either.
Could such an agent lurk either in the White House or the former Naval Observatory where the Bushes lived for eight years, from 1981 to 1989, when Mr. Bush was vice president?
Last summer, three and a half years after she joined the Bush household, Millie, a springer spaniel who has been the subject of a best-selling book, developed what was later diagnosed as lupus. The uncommon disorder of humans and dogs can cause a butterfly-shaped rash on the face; anemia, arthritis and kidney damage. Lupus is considered a classic model of an autoimmune disease.
Millie's malady has been treated with a steroid drug, prednisone, said Dr. Lee. "She was given a bad prognosis, but now she is doing pretty well, off prednisone," he said.
As in humans, the cause of lupus in dogs is unknown, but environmental factors seem to be important. Although some reports have hinted at links between lupus in families and in their household pets, documented transmission from dogs to humans lacking.
Graves' disease is another classic autoimmune disorder. It causes the thyroid gland in the neck to produce too much of the hormone that controls the body's metabolism.
