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In 1996 the Diagnostic Criteria for Marfan Syndrome were revised. The diagnosis of Marfan syndrome can be difficult because there is no specific laboratory test that is conclusive in diagnosis. Rather, a composite of clinical findings are required to make the diagnosis of Marfan syndrome in an individual. The diagnostic evaluation for Marfan syndrome should be performed by physicians experienced with the condition and should include the following: - Detailed medical and family history.
- Complete physical examination.
- Thorough eye examination by an ophthalmologist using a slit lamp to look for lens dislocation after fully dilating the pupil.
- Echocardiogram looking for involvement of the cardiovascular system.
The diagnosis of Marfan syndrome is based on the clinical findings of the evaluation outlined above. The criteria for diagnosis are classified into major or minor criteria based on how specific the clinical finding is for Marfan syndrome. Major criteria are clinical features that are highly specific for Marfan syndrome and rarely occur in the general population. Minor criteria are features that are present in individuals with Marfan syndrome, but also often present in the general population. The diagnosis requires that at least two of the major manifestations of the condition be present in patients without other affected family members. In families in which Marfan syndrome is known to occur, only one major criterion is required. The major features necessary for the diagnosis include the following:
- Aortic root enlargement (aortic aneurysm)
- Aortic dissection
- Lens dislocation
- Dural ectasia
- Presence of at least 4 major skeletal features, which include chest wall deformities, long, thin arms and legs (assessed by detailed measurements), and scoliosis greater than 20 degrees
You may wish to print out Marfan syndrome Diagnostic Criteria Checklist for Medical Records to include in your patient files. The following table briefly summarizes the diagnostic criteria for Marfan syndrome: | Body System | Major Criteria
| Minor Criteria
| | Skeletal System | Major criteria of the skeletal system are met when a person has at least 4 of these features: - A chest that sticks out (pectus carinatum)
- A chest that sinks in so much as to need surgery (pectus excavatum).
- Arm span greater than height. This means that when your arms are stretched to the side, the distance from finger tip to finger tip is greater than your height.
- Reduced upper to lower segment ratio. This is when the length of your torso (from shoulders to legs) is shorter than the length of your legs.
- Positive wrist sign. This is when your thumb and little finger overlap when you grasp the other wrist.
- Positive thumb sign. This is when you put your thumb on your hand and it extends beyond the palm.
- Curvature of the spine (scoliosis) with a curve greater than 20 degrees.
- Vertebrae (spine bones) that slip over each other (spondylolisthesis).
- Flat feet (pes planus).
- Extra-deep hip sockets (where the thigh bone meets the hip). This is also called “protrusion acetabulae” and doctors find it by hip x-ray.
| - A chest that sinks in, but not so much as to need surgery.
- Very flexible joints throughout your body.
- The palate (roof) of your mouth is highly arched and the teeth are very crowded.
- Certain facial features such as: a long, thin face; deep-set eyes; receding chin; or down-slanting eyes.
| | Cardiovascular System | - The part of your aorta closest to the heart bulges out or is enlarged (ascending aortic dilation or aneurysm).
- The layers of the ascending aorta are separated and may tear (dissection of the ascending aorta).
| - A “floppy” mitral valve (mitral valve prolapse, or MVP).
- Enlarged pulmonary artery without any known cause, before age 40.
- Calcium deposits in the mitral valve, before age 40
- A part of the aorta – either in the chest (descending thoracic aorta) or stomach (abdominal aorta) – is enlarged, before age 50.
- Tearing (dissection) of the aorta in the chest or stomach, before age 50.
| | Pulmonary System | There are no major criteria of the pulmonary system. | - Sudden collapse of the lung for no known reason (spontaneous pneumothorax)
- Extra-large air sacs at the top of the lung (apical blebs). These are found by chest x-ray.
| | Skin | There are no major criteria of the skin.
| - Skin stretch marks, not due to pregnancy or weight gain.
- Two or more hernias (recurrent hernia).
| | Dura | Dural ectasia. This is found with CT or MRI scans of the back. | There are no minor criteria of the spinal column sac. |
Requirements for the Diagnosis of Marfan Syndrome
The diagnosis of Marfan syndrome is a complicated clinical decision based on the minor and major features present in an individual and is summarized below.
For the index case:
- If the family/genetic history is not contributory, major criteria in at least 2 different organ systems and involvement of a third organ system
- If a mutation known to cause Marfan syndrome in others is detected, one major criterion in an organ system and involvement of a second organ system
For a relative of an index case:
- Presence of a major criterion in the family history and one major criterion in an organ system and involvement of a second organ system
Please note that some of the criteria used to diagnosis Marfan syndrome arise with age. Therefore, a child may fail to meet the criteria at first, but may have manifestations that definitely meet the criteria at a later date. This phenomena of partial expression of Marfan syndrome in a child that one suspects will meet the full criteria at an older age has been termed "emerging Marfan syndrome". While molecular testing for Marfan syndrome may be helpful in certain circumstances, a clinical diagnosis is still required. For a list of laboratories that offer the test, please visit http://www.genetests.org/
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