Mona Lisa's smile is often described as enigmatic, but could the mysterious allure of this iconic painting actually be due to an underlying illness in "Lisa" herself?
At least one doctor thinks so. In a Letter to the Editor in the September issue of the journal Mayo Clinic Proceedings, a cardiologist and his colleague take a detailed look at the painting, and speculate that Lisa Gherardini, the subject of the painting, may have had hypothyroidism, or an underactive thyroid gland.