Causes and Diagnoses

Causes and Diagnoses for Marfan Syndrome

Marfan is an inherited disorder, passed down genetically from a parent.

  • It’s estimated to occur in at least 1 in 5,000 persons
  • In most cases, Marfan syndrome is “autosomal dominant,” which means it occurs equally in men and women
  • The condition can be inherited from just one parent with Marfan syndrome
  • A patient with Marfan syndrome has a 50 percent possibility of passing on the gene that causes Marfan syndrome to an unborn child
  • Marfan syndrome is a “variable expression” genetic disorder meaning not everyone experiences the same symptoms or abnormalities to the same degree despite having the same defective gene

Diagnosing Marfan syndrome

The majority of patients with Marfan syndrome can be diagnosed based on clinical findings alone, but genetic testing may be able to identify the specific mutation to determine if other family members are affected. To establish the diagnosis:

  • Patients with suspected Marfan syndrome may be tested for the fibrillin-1 gene (FBN1) mutation, specific to Marfan syndrome
  • Patients with suspected Loeys-Dietz syndrome may be tested for the TGFBR1 and TGFBR2 gene
  • Patients with suspected vascular type (Type IV) Ehlers-Danlos syndrome may be tested for the COL3A1 gene

Generally, if there are others in the family who have been diagnosed with Marfan syndrome, at least two of these body systems must be affected to confirm the diagnosis. If no family history of Marfan syndrome is present, at least three body systems need to be affected to confirm the diagnosis.

If you have Marfan syndrome, the Bluhm Cardiovascular Institute recommends that your first-degree adult relatives (parents, siblings and children) be screened by a physician familiar with Marfan syndrome. This may include genetic testing, which involves sending a blood sample to a genetic testing company.


An evaluation for Marfan syndrome at the Marfan Syndrome and Related Disorders Clinic may include the following tests for diagnosis and follow-up:

Meet the Marfan Syndrome Team

Northwestern Medicine Bluhm Cardiovascular Institute is a nationally recognized destination for those who require highly specialized cardiovascular care.
Meet the Team
Downtown Chicago