Playwright Jonathan Larson sought help at two New York City emergency rooms before he died.

Doctors at the first attributed his chest pains to food poisoning. A few days later, at a second hospital, Larson was told he had the flu.

No one correctly diagnosed that he had a heart defect caused by Marfan syndrome.

On January 25, 1996, Larson died alone in his apartment when an artery carrying blood away from his heart enlarged and ruptured. He was 35. It was just one week before his hit play, "Rent," opened on Broadway. 

It was only after Larson''s death that his family learned that he had Marfan''s.

Tragic scenarios such as this one aren''t unusual.

Larson''s situation "is like one of the dozens of examples I hear about each year, of people who weren''t diagnosed with Marfan syndrome until they suffered an aortic dissection or died," said Dr. Alan Braverman, a cardiologist who heads the Marfan Clinic at Barnes-Jewish Hospital and Washington University.

The clinic is one of a few of its kind nationwide to offer evaluation and treatment of Marfan syndrome by doctors of various specialties at one site.

Braverman''s own father didn''t know he had Marfan''s and died at 46 of a ruptured aorta.

An estimated 10,000 people in the United States each year experience an aortic dissection. The exact number is unknown because the condition often goes undiagnosed.

If it''s not caught in time, half of those who experience it die within 48 hours. The condition often occurs in people in their 30s and 40s who outwardly appear healthy.

Working in partnership with the National Marfan Foundation, Braverman has been leading a nationwide effort to improve diagnosis of the disorder in emergency rooms. The initiative developed educational materials and a training video to help emergency room staff learn how to correctly recognize, diagnose and treat a dissection.

Diagnosis can be tricky. Emergency room doctors are being advised to suspect Marfan''s if they see a young person with unexplained chest pain who exhibits a cluster of physical characteristics, some of which can be subtle. Many people without Marfan''s also share these traits, while others with the disorder exhibit only some of them.

Larson exhibited many of the outward signs of Marfan syndrome, including a height taller than other family members, disproportionately long arms, legs, fingers and toes, nearsightedness and a curved spine.

Since people with long arms, fingers and legs often are recruited for sports, some people with Marfan's become star athletes, only to die young when their aortas rupture. Among them were Chris Patton, a University of Maryland basketball star who died in a pickup game in 1976, and Flo Hyman, an Olympic volleyball player who died at 31 in 1986.

Although emergency room doctors don''t always recognize symptoms, they likely will see 10 to 15 patients with Marfan syndrome during their careers. That means they''ll probably see more cases of Marfan''s than of pulmonary TB or meningitis.

John Torode, 31, of Kirkwood, was sent home after an ER visit when his dissection went undiagnosed.

"They didn''t offer a diagnosis, but hinted it might be a virus or whooping cough," he said. "I wasn''t confident with the explanation but felt I had done everything else I could do. I was at a loss. I felt at the mercy of the doctors because there wasn''t anything else I could do."

Torode shuffled between several doctors and two emergency rooms over a three-week period in 1999 before his dissection was diagnosed. By then, he was at the brink of death.

Emergency surgery repaired his torn aorta, and he has had two heart valves replaced. Today, he''s doing well.

The primary symptom of an aortic dissection is severe pain, usually in the chest. But if the tear begins in the lower part of the aorta, it can also be felt in the abdomen. Other signs are pallor, lack of pulse and paralysis.

An imaging study - such as a standard echocardiogram, a MRI, a CT scan or transesophageal echocardiogram - can confirm or disprove a diagnosis of a ruptured aorta.

Marfan syndrome can be diagnosed by a physical exam, including an echocardiogram by a cardiologist, a measurement of body proportions by a geneticist or orthopedist, and a slit lamp exam by an ophthalmologist.