Overview

Marfan syndrome (MFS) is a rare genetic disorder that affects the body’s connective tissue, which supports and gives structure to the organs and other tissues.¹ MFS can be passed down from your parents, but it is not necessary to have a family history to get MFS. Scoliosis is a spinal deformity which can cause the spine to curve and rotate.² MFS affects the skeleton and so can affect the spine of people with this disorder. Scoliosis is very common, occuring in about 60% of people with MFS.³

Marfan syndrome 

MFS is caused by a genetic mutation, which is where the normal sequence of your DNA is altered. In MFS, the mutation is in the FBN1 gene, which affects a specific protein called fibrillin-1.¹ This protein's job is to help your body’s cells attach and form supportive structures. Because of the mutation in this protein, people with MFS typically have features affecting the heart, eyes, and skeleton.⁴ Even though MFS is congenital, which means it is present from birth, the age you can get diagnosed can be in the late teenage years. This is because you may not have obvious MFS symptoms in childhood, but will develop them with age.⁵ 

The risk of being born with MFS is equal in both men and women⁴ and increases if there is a family history of the disorder, as it is hereditary so can be passed down. However, it is not necessary to have a family history to get MFS.¹ You can still get a MFS diagnosis if the criteria is met even if there is no mutation found in the FBN1 gene.⁴

Diagnosis of MFS in adults is done through Ghent criteria.⁶ This contains different criteria for the different systems like the heart, skeleton, eyes, skin and lungs.⁷

The Ghent criteria works by a point system. Each MFS criteria has a number of points, and a score can be calculated to determine a diagnosis.⁷ 

Skeletal symptoms of Marfan syndrome:

• Pectus carinatum - also known as pigeon chest
• Pectus excavatum - also known as funnel chest
• Asymmetrical chest
• Reduced upper to lower segment ratio of your body 
• Increased arm span relative to your height
• Hindfoot deformity or flat feet
• Scoliosis
• Kyphosis 
• Positive wrist sign - where your thumb overlaps your fifth finger when clasping your other wrist
• Positive thumb sign - where you overlap your thumb with your other fingers, and your thumb extends over the border of your hand
• Protrusio acetabuli - a defect in your socket causing the hip is displaced⁸
• Reduced ability to extend your elbow 
• Deformities in facial features

Some people with MFS may have milder symptoms, and so also get a late diagnosis.⁵

It should be noted that Ghent criteria should not be used for children,⁶ and other diagnostic tests can be conducted.¹ 

How Marfan syndrome causes scoliosis? 

As MFS is a disorder that weakens the body’s connective tissue, this can cause loosened joints and the bones of the skeleton to grow longer, this leads to scoliosis.¹ Certain aspects of MFS are only visible as you get older, and scoliosis is one of the age dependent symptoms of MFS.⁶

Scoliosis is when your spine deviates from a vertical straight spine in your back, with your vertebrae, the small bones in your spine, curving.² Scoliosis spinal curve patterns are either classed as typical or atypical. This means the spine curvature is either commonly seen or rarely seen in patients.⁹ 

MFS scoliosis curve patterns:

• Atypical 
• Typical with features of an atypical curve⁹

Most cases of scoliosis are called idiopathic, which means that the cause of the scoliosis is unknown.² In MFS scoliosis is syndrome-related and called non-idiopathic, as we know the cause.⁹ 

Scoliosis is the most common deformity of the spine associated with MFS.¹⁰ The way MFS causes scoliosis is not only by the genetic mutation of the DNA sequence of the FBN1 gene, but also by the effects of epigenetic changes that are associated with the disorder. This is where your DNA sequence is not mutated, but the physical effects can be seen because these changes can switch your genes on or off.¹¹

How MFS scoliosis differs from adolescent idiopathic scoliosis (AIS)?:

• Scoliosis seen in earlier age in MFS
• Increased scoliosis severity 
• More curve patterns that are double curves and triple major curves
• Increased likelihood of developing hyperkyphosis - a severe forward spine curvature in the mid and upper back
• Less likelihood of developing hypokyphosis - a loss of curvature in the middle and upper back
• In MFS, both men and women equally develop scoliosis, whereas in AIS, scoliosis is more common in women¹²

There are varying degrees of curvature of your spine in scoliosis. The degrees are measured by the Cobb angle method to determine the severity of scoliosis.¹³

Cobb angle scoliosis:

• Spinal curve is 0°-10°
• Mild scoliosis is 10°-20°
• Moderate scoliosis is 20°-40°
• Severe scoliosis is >40°

The lower the degrees of curvature, the less severe the scoliosis. Different treatments will be available depending on the severity of you scoliosis.¹² 

Scoliosis diagnosis 

The symptoms that show up in MFS are diverse amongst patients. Therefore, your doctor will diagnose and evaluate scoliosis from MFS through a mixture of tests.¹⁴

Scoliosis tests:

• Physical examination²
  • Forward bending test - where you bend forward and spine asymmetry is measured
• X-ray (radiography) to image your spine²
• Magnetic resonance imaging (MRI)¹⁵
• Computed tomography (CT) scan¹⁵

Part of the physical examination includes looking at your gait, your shoulders and hips for asymmetry, and conducting the forward bending test. During the physical tests, your doctor will look for spinal asymmetry.² In the physical examination your physician will also look for other abnormalities, like long fingers and an increased arm span to height ratio to diagnose that the scoliosis is part of MFS.²

After the physical exam your doctor will image your spine using x-rays to see the severity of your scoliosis.² Further imaging of your spine with MRIs or a CT scan may also be conducted.¹⁵

Scoliosis MFS treatment 

Scoliosis remains a major challenge for treatment in MFS.¹² Treatment for scoliosis in patients with MFS typically includes surgical correction. There are different types of surgery depending on the severity of your scoliosis. These methods are usually using devices for a three-dimensional correction.¹⁰

MFS scoliosis treatments:

Non operative 

• Bracing¹⁶

Operative

• Fusion surgery¹⁰
  • Posterior spinal fusion - surgery at back of your spine¹⁰

A spinal brace is a device that applies pressure to your spine to prevent worsening of scoliosis and helps correct the curvature. The brace can be used on spinal curves with angles between 20 and 40 degrees.¹⁶ Bracing may not work in helping scoliosis associated with MFS.¹⁰ This is because MFS patients are more likely to have a higher spinal curve rigidity, an earlier age of scoliosis appearing, and a lower tolerance for bracing.¹²

Fusion surgery is where vertebrae, your spinal bones, are joined together to give your back structure and correct the scoliosis curves.¹⁰ The surgery uses metal screws and other equipment to fuse the vertebrae.¹⁶

It should also be noted that surgery to correct scoliosis in patients with MFS is more difficult than in patients with AIS. This is because MFS patients have weaker bones and a high risk of scoliosis progression. There are also surgical complications like blood loss, lesions on the spine and the bones not fusing properly after surgery.¹⁰ You can discuss these risks with your surgeon.

Summary 

Marfan syndrome is caused by a genetic mutation in the fibrillin-1 protein, and is a systemic disorder of connective tissue, which can affect your skeleton.¹ Scoliosis is the most common spinal deformity amongst individuals with MFS.¹⁰ Surgical treatment may be required to treat severe scoliosis associated with MFS.¹⁶ Contact your healthcare professional for advice.