Proteus syndrome causes an overgrowth of skin, bones, muscles, fatty tissues, and blood and lymphatic vessels. Proteus syndrome is a progressive condition wherein children are usually born without any obvious deformities. Tumors of skin and bone growths appear as they age typically in early childhood. The musculoskeletal manifestations are cardinal for the diagnosis of Proteus syndrome. The severity and locations of these various asymmetrical growths vary greatly but typically the skull, one or more limbs, and soles of the feet will be affected. There is a risk of premature death in affected individuals due to deep vein thrombosis and pulmonary embolism caused by the vessel malformations that are associated with this disorder. Because of carrying excess weight and enlarged limbs, arthritis and muscle pain may also be symptoms — as is the case for Mandy Sellars, a woman who has been diagnosed with a form of Proteus syndrome (but see "Notable Cases" below). Further risks may occur due to the mass of extra tissue.