Warning raised on genetic disorder

MINNEAPOLIS -- A genetic disorder first described just one year ago is more widespread than doctors realize, and misdiagnosing it may be deadly, researchers said.

Loeys-Dietz syndrome is a connective tissue disease marked by convoluted blood vessels and a weakened aorta that can fatally rupture, researchers said after studying patients from 52 families. As a result, treatment should be more aggressive for Loeys-Dietz than for similar disorders that are often mistakenly diagnosed for the syndrome.

``It's very important to recognize this condition and distinguish it from other connective tissue disorders," like Marfan's, said Harry Dietz, director of Johns Hopkins University School of Medicine's Center for Marfan Syndrome Research. Misdiagnosis may result in ``avoidable death," he said.

Patients with Loeys-Dietz are often misdiagnosed as having Marfan's syndrome , known for causing a lankiness like that of Abraham Lincoln, or the vascular disorder called Ehlers-Danlos syndrome, the researchers said. Loeys-Dietz, though, is the only one of the three in which the aorta may rupture even when it doesn't seem dangerously enlarged, Dietz said in a telephone interview yesterday.

Nearly all Loeys-Dietz patients survive surgery to repair the vessel, said Dietz, who identified the disorder in February with Bart L. Loeys from Hopkins's Institute for Genetic Medicine and the Center for Medical Genetics at Ghent University Hospital in Belgium.

At the time, the two scientists knew of only 10 patients with the condition. The latest study, published in today's New England Journal of Medicine, reviewed data on clinical care, cardiovascular complications, and the genetic makeup of 90 patients.

Since the syndrome was identified ``we've learned that cardiovascular surgery is very safe and therefore you should be very aggressive about going in and repairing these aneurysms before they rupture," Dietz said. ``In contrast, in people with vascular Ehlers-Danlos syndrome, you don't do surgery unless you believe death is imminent," he said.

More studies are needed to pinpoint the exact number of people with the condition in the United States and worldwide, Dietz said.

About one new family a week has come to the genetics center at Hopkins with Loeys-Dietz syndrome since it was identified, even though there was no advertising or publicity designed to raise awareness about the condition, Dietz said.

The disease can lead to aggressive arterial aneurysms, with death at an average age of 26.