Marfan, Loeys-Dietz Diagnosis Made Simple

Aug. 4, 2010— -- A simple signs-and-symptoms checklist could help primary care physicians spot patients with Marfan syndrome or Loeys-Dietz syndrome -- genetic conditions that, if untreated, can be deadly.

In two separate studies appearing in the August issue of the Journal of Bone and Joint Surgery, research teams led by Dr. Harry C. Dietz and Dr. Paul Sponseller of Johns Hopkins University in Baltimore, Md., suggest the checklist could help patients receive the monitoring and treatment necessary to prevent these genetic diseases from becoming life-threatening.

Marfan syndrome and Loeys-Dietz syndrome are both caused by mutations in specific genes. Both gene defects lead to visible bone abnormalities, as well as less visible but more serious cardiovascular problems such as aneurysms.

The severe complications of Loeys-Dietz syndrome can occur in young adulthood, making an appropriate diagnosis important so that monitoring and preventive treatment with drugs that lower blood pressure and even surgery can be administered in time.

"Patients may be diagnosed by their pediatrician, their family physician, their internist, eye doctors especially, and general orthopedic surgeons," Sponseller said in an interview.

Because many of the clinical features aren't pathologic by themselves -- such as long thumbs, narrow skulls, and flat feet -- it's important not to send too many patients for expensive genetic testing or cardiologic evaluations, he said.

Consequently, the researchers sought to develop relatively short lists of signs and symptoms, such as narrow skull, long thumbs, and flat feet, that would warrant referring patients to a specialist.

The combination of facial features and the "thumb sign" was both highly specific and sensitive for diagnosis in a study of 183 Marfan patients and 1,257 controls, Sponseller and colleagues reported.

They also noted two other features that were found in some Marfan patients but virtually never in healthy controls: a widening of the sac that surrounds the spinal cord and a defect of the hip socket.