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Disease Profile

Susac syndrome

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

All ages

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ICD-10

I67.7

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Retinocochleocerebral vasculopathy; SICRET (small infarction of cochlear, retinal, and encephalic tissue) syndrome

Categories

Blood Diseases; Kidney and Urinary Diseases; Nervous System Diseases

Summary

Susac syndrome is an autoimmune condition that affects the very small blood vessels in the brain, retina, and inner ear (cochlea). The condition is characterized by three main symptoms: brain disease (encephalopathy), hearing loss, and vision loss. Some people may not have all signs of Susac syndrome, but instead develop only specific combinations of the symptoms. Susac syndrome affects women more than men. The age at which symptoms begin is usually between 20 and 40 years, but some people have symptoms earlier or later than this age range.[1]

The cause of Susac syndrome is still unknown. Diagnosis is based on a clinical exam and imaging tests to look for the specific signs of Susac syndrome.[2] Treatment options include corticosteroids and cyclophosphamide as well as anticoagulation medications. Most people recover from Susac syndrome with treatment.[1] 

Symptoms

The symptoms and severity of Susac syndrome can vary person to person. The three main parts of the body that are affected are the brain, eyes, and ears. However, all three body parts are not affected in all people with Susac syndrome.[1]

A headache is often one of the earliest symptoms of Susac syndrome. Recurrent headaches may be a sign of encephalopathy, or brain disease. Other neurological symptoms may develop including walking difficulties (ataxia), slurred speech (dysarthria), and cognitive changes including memory loss, confusion, and personality or behavioral changes.[3] In some cases, affected individuals may have urinary dysfunction or muscle pain (myalgia).[4]

Affected people may also have specific findings in the eyes called branch retinal artery occlusions (BRAO). This occurs when one of the blood vessels that supply blood to the retina (retinal arteries) become blocked. This can cause dark spots in the vision, but some people have no symptoms of BRAO.[1] 

Susac syndrome can also cause hearing loss due to poor circulation to the ears. Ringing in the ears (tinnitus) may also be present. The ears also have a role in regulating our balance. Therefore, some people with Susac syndrome experience vertigo and feel like their surroundings are spinning.[1] 

People with Susac syndrome may find that their symptoms go away and return again over a period of years. Other people experience symptoms only once, and after treatment the symptoms go away completely. Although the condition may resolve on its own, some people can develop long-term neurological damage, vision loss, or hearing loss.[5]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Headache
Headaches
0002315
30%-79% of people have these symptoms
Abnormal corpus callosum morphology
0001273
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment

[ more ]

0100543
Confusion
Disorientation
Easily confused
Mental disorientation

[ more ]

0001289
Generalized hypotonia
Decreased muscle tone
Low muscle tone

[ more ]

0001290
Sensorineural hearing impairment
0000407
Visual loss
Loss of vision
Vision loss

[ more ]

0000572
5%-29% of people have these symptoms
Abnormality of eye movement
Abnormal eye movement
Abnormal eye movements
Eye movement abnormalities
Eye movement issue

[ more ]

0000496
Apathy
Lack of feeling, emotion, interest
0000741
Diplopia
Double vision
0000651
Dysarthria
Difficulty articulating speech
0001260
Gait ataxia
Inability to coordinate movements when walking
0002066
Lethargy
0001254
Muscle weakness
Muscular weakness
0001324
Nausea and vomiting
0002017
Personality changes
Personality change
0000751
Psychosis
0000709
Sensory impairment
0003474
Tinnitus
Ringing in ears
Ringing in the ears

[ more ]

0000360
Upper motor neuron dysfunction
0002493
Vertigo
Dizzy spell
0002321

Cause

The exact cause of Susac syndrome currently is not known. The condition is thought to be an autoimmune disorder. Autoimmune disorders occur when the immune system (which fights off infections) mistakenly attacks the tissues of the body. When this occurs, it can cause swelling of the small blood vessels that supply blood to the brain, retina, and inner ear. This swelling can cause the blood vessels to completely close up so that parts of the body are not getting enough blood or oxygen. The symptoms of Susac syndrome are caused by damage to small blood vessels and the decreased ability of these blood vessels to carry blood and oxygen.[1]

Diagnosis

The diagnosis of Susac syndrome may be suspected based on a thorough clinical evaluation, a detailed medical history, and a variety of specialized tests. These tests may include magnetic resonance imaging (MRI). In people with Susac syndrome, an MRI can show characteristic changes in the brain, especially the corpus callosum. These findings are specific to Susac syndrome.[6]

A complete eye exam is also done to diagnose Susac syndrome. This eye exam will include a fluorescein angiography, which measures the blood flow through the retina. Other tests include a hearing exam to test for hearing loss and analysis of the cerebrospinal fluid, which may show high protein levels.[7] 

Susac syndrome can mimic several diseases, including multiple sclerosis, acute disseminated encephalomyelitis, chronic encephalitis, aseptic meningitis, Lyme disease, cardioembolic disorder, complicated migraine, systemic lupus erythematosus, Bechet syndrome, sarcoidosis, tuberculosis, syphilis, lymphomas, and Creutzfeldt-Jakob disease.[3][8][9]

Treatment

Early, aggressive, and sustained treatment of Susac syndrome is recommended to avoid or minimize neurological damage, hearing loss, and vision loss. Treatment includes medications that suppress the activity of the immune system (immunosuppressive therapy) so that it does not attack the blood vessels in the brain, eyes, and ears. Immunosuppressive medications may include high doses of corticosteroids, cyclophosphamide, and intravenous immunoglobulins. Doctors may also recommend blood thinners such as aspirin in order to prevent clotting in the small blood vessels.[5] Once treatment has improved symptoms, the medications can be slowly tapered off.[1]

Alternative treatments such as mycophenolate mofetil may be helpful in cases that don’t improve with other treatment. Overall, medications for Susac syndrome can prevent more symptoms from developing and improve symptoms of the condition, but the treatment may not be able to repair neurological, hearing, or visual damage. In some cases, people with severe hearing loss may benefit from cochlear implants.[4] 

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Social Networking Websites

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        Where to Start

        • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
        • The The Cleveland Clinic Web site has an information page on Susac syndrome. Click on the Cleveland Clinic link to view this page.

          In-Depth Information

          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Susac syndrome. Click on the link to view a sample search on this topic.

            References

            1. Rennebohm R, Egan RA, and Susac JO [now deceased]. Susac's Syndrome. National Organization for Rare Disorders (NORD). 2015; https://rarediseases.org/rare-diseases/susacs-syndrome/.
            2. Rennebohm RM, Lubow M, Rusin J, Martin L, Grzybowski DM, Susac JO. Pediatr Rheumatol Online J. January 2008; https://www.ped-rheum.com/content/pdf/1546-0096-6-3.pdf.
            3. Do TH, Fisch C, Evoy F. Susac Syndrome: Report of Four Cases and Review of the Literature. Am J Neuroradiol. March, 2004; https://www.ajnr.org/cgi/content/full/25/3/382.
            4. Jan-Markus Dorr. Susac syndrome. Orphanet. September, 2013; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=838.
            5. Aubart-Cohen, et.al.. Long-Term Outcome in Susac Syndrome. Medicine. March 2007;
            6. Rennebohm, Robert; Susac, John. Journal of Neurological Sciences. February 26,2007; https://www.ncbi.nlm.nih.gov/pubmed/17324441.
            7. Star M, Gill R, Bruzzone M, De Alba F, Schneck MJ, and Biller J. Do not forget Susac syndrome in patients with unexplained or acute confusion. Journal of Stroke and Cerebrovascular Diseases. April 2015; 24(4):e93-95. https://www.ncbi.nlm.nih.gov/pubmed/25680663.
            8. Susac JO. American Journal of Neuroradiology. March 2004; 25(3):351-352. https://www.ajnr.org/cgi/content/full/25/3/351.
            9. Sandhya V, Anand N. Susac Syndrome: A Case Report. Eye. November 2002; 16:788–790. https://www.nature.com/eye/journal/v16/n6/pdf/6700170a.pdf.
            10. Saux A, Niango G, Charif M, Morales R, Mura F, Bonafe A, and Mourand I. Susac’s syndrome, a rare, potentially severe or lethal neurological disease. Journal of the Neurological Sciences. October 15, 2010; 297(1-2):71-73. https://www.ncbi.nlm.nih.gov/pubmed/20723912.

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