Despite trying his best to hide his handicap during his lifetime, it's now common knowledge that Franklin Delano Roosevelt was in a wheelchair because he was paralyzed by the polio virus. But a new study suggests that the president may have actually been paralyzed by Guillain-Barre Syndrome. If true, it would make his polio diagnosis one of the most famous misdiagnoses in history.

The problems started in 1921, when the 39-year-old former Vice Presidential nominee went on a family retreat in Canada. Over the next two weeks, he started to become paralyzed and soon lost control of his bowels after the paralysis spread into his torso. After his party lost to the Republicans, Roosevelt retreated into private life to deal with his condition. By the time he was elected president in 1933, he was rarely seen in his wheelchair, though he did sometimes use a cane.

Roosevelt's doctor had extensive experience working with polio patients and believed that FDR had been exposed to the virus during a visit to a Boy Scout camp a few weeks earlier. But there are a number of issues with the polio diagnosis. For one, polio primarily affects children. The disease generally only affects one side of the body, not both—and it usually doesn't affect the intestinal tract. Finally, throughout his life, the future president continued to feel pain in his legs, but polio patients lose all sense in the affected areas.

Guillain-Barre Syndrome was a rather obscure condition at the time, so even if that is what FDR suffered from, it's entirely possible that his doctors had never even heard of the disease. While it was too late to obtain a spinal fluid sample for official testing, a 2012 study published in the Journal of Medical Biography concluded that the president almost certainly suffered from Guillain-Barre Syndrome, not polio, based on his symptoms.

Even if his doctors did properly identify what FDR was suffering from, there still wasn't much they could have done to treat it—so at least the probable misdiagnosis didn't dramatically change Roosevelt's quality of life. Additionally, knowledge of the president's condition helped bring polio into the public consciousness, and his founding of the National Foundation for Infantile Paralysis in 1937 eventually led to Jonas Salk receiving the grants he needed to develop a vaccine to prevent the disease. In this way, this possible misdiagnosis ended up saving thousands of lives.