Bones and Joints | The Marfan Foundation

The Marfan Foundation

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Bones and Joints

Marfan syndrome often causes problems in the bones and joints, and these are often the features that first lead a person to suspect Marfan syndrome. These features (called skeletal features) happen when bones grow extra long or ligaments (connective tissue that holds joints together) become stretchy – like loose rubber bands. 

Many people with Marfan syndrome have more than one skeletal feature. Very few people have them all. Only about one-third of people with Marfan syndrome have skeletal features so severe that they need to see an orthopedic doctor. Here are some problems that can happen.

When bones grow extra long:

  • Your chest may sink in (pectus excavatum) or stick out (pectus carinatum or pigeon breast). This happens when your ribs grow too long.
  • Your arms, legs, fingers, and toes can be very long and thin. Your doctor may check whether they are extra long by using any of these measures:
    • Arm span greater than height (when you stretch out your arms to the side and the measurement from finger tip to finger tip is more than your height)
    • Reduced upper to lower segment ratio (when the length of your torso [shoulders to legs] is much shorter than the length of your legs)
    • Positive wrist sign (when the thumb and little finger overlap when one hand grasps the other wrist)
  • Your teeth may be crooked and crowded because the roof of your mouth (palate) is high and arched.
  • Your hip sockets (where the thigh bone fits into the hip) are extra deep. Doctors often find this problem by doing a hip x-ray.

When ligaments are stretchy and loose:

  • You may have a very low foot arch (pes planus or flat feet) or very high foot arch.
  • Your spine may curve to the side (scoliosis) or forward (kyphosis).
  • Bones in your spine (vertebrae) may slip over each other (spondylolisthesis). This most often happens in the lower spine.
  • You may have extra movement (hypermobility) in your hand and wrist. This can make it hard to hold pencils or pens.
  • Your knees, hips, shoulders, or other joints may slip out of place (dislocate).
  • You may have claw or hammer toes (abnormal bending of the toes).
  • You may get arthritis as early as your 20’s or 30’s. Deep hip sockets or unstable joints can cause this.

Other skeletal features may include:

  • Reduced bone density (which can make your bones weak). Doctors are studying whether people with Marfan syndrome are at greater risk for getting broken bones or if their broken bones heal more slowly.
  • Swelling or bulging of the sac (dura) around your spinal cord (dural ectasia). This is common in people with Marfan syndrome. Doctors test for dural ectasia with MRI or CT scans of the lower back. For more information on dural ectasia, go to Nervous System.

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Bones & Joints in Marfan syndrome