Lacy Chambers, then 11, was playing volleyball when her shoulder slid out of its socket the first time. She had two surgeries over the next three years.

When she was 14, she was walking on the porch when her hip dislocated. That time, she was in a wheelchair for six weeks, able to leave it for only very small journeys. Two weeks after that, her other hip dislocated as she was getting up. She was placed in leg braces and a wheelchair for another six weeks.

Then her jaw dislocated, followed by her neck, her fingers, her wrists, her ankles and her knees. She was home-schooled for a while, deemed too fragile to risk public school. Every joint, it appeared, was at risk. Once, another student, jostling past in the hallway, grabbed her arm and the shoulder popped out again.

Kim Hansen was hospitalized for internal bleeding after a blood vessel ripped open when he was jogging. Another time, at work, a pipe hit him in the head and a blood vessel started leaking into his nasal cavity. Doctors had to do brain surgery, including tying off a carotid artery.

One day, playfully wrestling with his two young children, he sustained a little kick to the abdomen and was hospitalized for internal bleeding, which was expected to stop on its own. It didn't. He died from the damage to his organs. He was 36.

Though their symptoms appear to have nothing in common, both Chambers and Hansen had Ehlers-Danlos syndrome, an inherited condition caused by a defect in connective tissue. According to the national foundation that bears the syndrome's name, fragile skin and tissue and unstable joints are the result of faulty production of collagen, a protein that acts as "glue" in the body.

There are six major types of EDS, each designated by their symptoms. Chambers' hypermobility is an example of the most common form, which is also the most painful. Fully 95 percent of cases are hypermobile, or vascular, like Hansen's, or "classical," which is associated with scarring, "stretchy" skin, extensive bruising, slower wound healing and various internal-organ issues, according to Terri Keyes of the Ehlers-Danlos National Foundation. Vascular EDS is the least common of the three, but it is the one that can cause premature death.

"All types are woefully underdiagnosed," says Keyes. "Lack of diagnosis increases the health risks for people who have this, especially in surgery and pregnancy, as extra precautions need to be taken to reduce risk and increase the possibility of a successful outcome. Surgeries on undiagnosed vascular type are extremely risky," also true to some degree for all types of the syndrome.