Sneddon Syndrome (SS)


Sneddon syndrome (SS) is a very rare genetic disorder that causes ischemic strokes in young adults.

Although the condition is not yet completely understood, researchers believe it is connected to a change in the CECR1 gene, which helps produce an enzyme called adenosine deaminase 2. When this enzyme is blocked, it may cause abnormalities in the lining of blood vessel walls.


Symptoms vary depending on the severity of the condition and the areas of the body affected. They may include:

  • Headache
  • Skin discoloration (livedo racemosa), most commonly on the limbs, abdomen and buttocks
  • Vertigo
  • Transient ischemic attack (TIA)
  • Stroke
  • Seizures
  • Dementia
  • Changes in behavior
  • Depression

Stroke is one of the main symptoms of SS. If you notice one or more of these signs in another person or in yourself, do not wait to seek help. Call 9-1-1 immediately.
The signs of a stroke are:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion
  • Sudden trouble speaking
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking
  • Sudden dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause

The effects of an acute ischemic stroke may cause additional symptoms in women including:

  • Face, arm or leg pain
  • Hiccups or nausea
  • Chest pain or palpitations
  • Shortness of breath

Causes and Risk Factors

Although it is not yet completely understood, SS may be caused by changes in the CECR1 gene, which helps produce an enzyme known as adenosine deaminase 2, which helps support the lining of blood vessel walls.

SS is very rare, affecting just 4 in every 1 million people each year. The condition occurs more often in women between the ages of 20 and 42. Reproductive hormones, oral contraceptives and high blood pressure have been associated with the condition. However, the condition can occur in both men and women at any age.

Although SS is thought to be genetic, with only one parent needing the abnormal gene for the child to develop the condition, current research has shown it also may occur in people with no family history of SS.


Diagnosis of SS usually begins with a physical exam and a review of the patient’s medical history and symptoms, particularly stroke episodes. A skin biopsy and genetic tests often are used to diagnose the condition.

Imaging tests, including magnetic resonance imaging (MRI) and computed tomography (CT), are used to help diagnose the condition and better understand the patient’s symptoms. MRI or CT scans also are used to see if there is any stroke-related damage to the brain. A cardiovascular evaluation will look at the heart and blood vessels and may include additional imaging tests such as an echocardiography or angiography.


There is no cure for Sneddon syndrome. Treatment plans focus on managing the patient's symptoms, and may include physical and occupational therapy and medications.

Blood thinning (anticoagulant) medications may be prescribed to help minimize the risk of stroke. If the patient has other risk factors, such as smoking or uncontrolled high blood pressure or diabetes, these conditions also will need to be treated. 

For patients who have experienced a stroke, the Stroke Program at Cedars-Sinai provides a multidisciplinary treatment approach through a personalized treatment plan tailored to each patient. Patient care is generally broken down into three categories: stroke prevention, treatment immediately after a stroke, and post-stroke rehabilitation.

For patients with a hereditary condition, genetic counseling, available through the Cedars-Sinai Medical Genetics Institute, can help identify families at risk and provide referrals to specialized health care providers.

© 2000-2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Want More Information?

Cedars-Sinai has a range of comprehensive treatment options.

Looking for a Physician?

Choose a doctor and schedule an appointment.

Need Help?


Available 24 Hours A Day

Need Help?


Looking for a Physician

Choose a doctor and schedule an appointment.