Detection of Marfan vs Loeys-Dietz syndromes

[caption id="attachment_12116" align="alignleft" width="300" caption="Marfan's syndrome, Myxomatous aortic valve"][/caption]

Editor - Medical research at John Hopkins has identified the characteristics of Marfan and Loeys-Dietz syndromes, which can mean life or death; but there are those with neither syndrome that can have those characteristics.

It can be confusing to those who are diagnosing Marfan vs Loeys-Dietz syndromes to note there are people who have certain identified characteristics of those and not have the syndromes themselves.


The information has been published in the August issue of the Journal of Bone and Joint Surgery, as two separate studies.


There are two lists that provide the identifiable physical characteristics that suggest either Marfan or Loeys-Dietz syndromes.  Certain features involving the face, skull, joints and spine can be spotted in a physical exam, although not always easy to sort out without additional information.

“The beauty of our lists is that they require no fancy imaging tests and most of the signs are right there for the pediatricians and the orthopedic surgeons to
see,” says co-investigator Paul Sponseller, M.D., M.B. A., director of Orthopaedics at Johns Hopkins Children’s Center. “All they have to do is
see the forest for the trees. The lists will help them do so.”

Both of these syndromes are treatable in order to prevent some of the life-threatening complications involving the heart.


“We miss that prevention opportunity in people diagnosed as adults,” Sponseller says.


Both Marfan and Loeys-Dietz syndromes affect the connective tissue of the heart, spine, joints and eyes.  Loeys-Dietz, however, also involves
twisted arteries that are prone to aneurysms.  This is a feature exhibited differently in this syndrome and because of it intervention
and treatment is often needed earlier. in Marfan.  

To identify the specific characteristics of Marfan, researchers began with the classic features that include long tapering fingers, a spinal curvature and a
long narrow face.  The researchers looked at 183 Marfan and 1,250 non-Marfan patients at Hopkins, then analyzed the frequency of certain
characteristics both with and without the disorder.

What researchers found is that the strongest diagnostic predictor of Marfan in the study was the combination of certain facial features with a very
long thumb. With a diagnostic accuracy index of 0.97, this combination correctly predicted Marfan in 97 out of 100 every patients.

A patient with any two of the following signs with high diagnostic potential should be sent to a Marfan specialist:


• One or more cranial or facial signs including a long lean skull,
downward slanted eyes, a receding jaw (diagnostic accuracy 0.93) • An
extra long thumb: when folded inside the clenched fist of the hand, the
thumb reaches the outer rim, past the pinkie (diagnostic accuracy 0.87) •
Wrist test: A thumb that covers the entire nail of the same-hand pinky
finger when encircling the wrist of the opposite hand (diagnostic
accuracy 0.83)

A patient with three or four of the following should be sent to a specialist:

• Cranial and facial features described above • High-arched palate •
Hollow chest • Severely flat feet, with or without deformity • Arm span
more than 1.5 times longer than the total height

Another
critical feature was the combination with curvature of the spine, or
scoliosis along with specific facial features and an extra long thumb.

The diagnostic tool, researchers remind us, is not perfect but helps to make it easier to identify Marfan's syndrome.


With the Loeys-Dietz study, 65 patients had been diagnosed, and then
researchers looked at certain signs not found in Marfan that include
widely spaced eyes, club foot, skin that is translucent and bruises
easily, bi-forked or split uvula, scoliosis with other spinal
deformities.