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Ataxia with Oculomotor Apraxia Type 2

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Other Names:
AOA2; SCAN 2; SCAR1; AOA2; SCAN 2; SCAR1; SCAN2; Autosomal recessive spinocerebellar ataxia-1; Ataxia-oculomotor apraxia type 2; Spinocerebellar ataxia with axonal neuropathy type 2 See More
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Spinocerebellar ataxia with axonal neuropathy type 2 (SCAN2) is a rare condition that affects muscle control and coordination. Ataxia (difficulty coordinating movements) is generally the earliest sign of the condition and is often diagnosed between age seven and 25 years. Other signs and symptoms may include sensorimotor neuropathy, mild cognitive impairment and less commonly, movement disorders. Approximately half of affected people also experience, oculomotor apraxia which makes it difficult to move the eyes from side-to side in the desired direction. SCAN2 is caused by changes (mutations) in the SETX gene and is inherited in an autosomal recessive manner.[1][2][3] Treatment is based on the signs and symptoms present in each person.[2]
Last updated: 9/28/2018
The signs and symptoms of spinocerebellar ataxia with axonal neuropathy type 2 (SCAN2) generally become apparent between age 7 and twenty five years. Ataxia is often the first symptom and is a major cause of disability in the early stages of the condition. Most people with SCAN2 also experience sensorimotor neuropathy which is associated with a decreased ability to move or feel (sensation) in certain parts of the body, especially the lower limbs. Other symptoms can include oculomotor apraxia, movement disorders, and mild cognitive impairment.[2][3][1]
Last updated: 6/1/2017

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.

Showing of 48 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Areflexia
Absent tendon reflexes
0001284
Ataxia 0001251
Cerebellar vermis atrophy 0006855
Sensorimotor neuropathy
Nerve damage causing decreased feeling and movement
0007141
30%-79% of people have these symptoms
Elevated alpha-fetoprotein 0006254
Gait imbalance
Abnormality of balance
Abnormality of equilibrium
Imbalanced walk
[ more ] 		0002141
Gaze-evoked nystagmus 0000640
Oculomotor apraxia 0000657
Saccadic smooth pursuit 0001152
Sensory impairment 0003474
5%-29% of people have these symptoms
Babinski sign 0003487
Choreoathetosis 0001266
Conjunctival telangiectasia
Small dilated blood vessels near membrane covering front of eye and eyelids
0000524
Dysphagia
Poor swallowing
Swallowing difficulty
Swallowing difficulties
[ more ] 		0002015
Dystonia 0001332
Elevated serum creatine kinase
Elevated blood creatine phosphokinase
Elevated circulating creatine phosphokinase
Elevated creatine kinase
Elevated serum CPK
Elevated serum creatine phosphokinase
High serum creatine kinase
Increased CPK
Increased creatine kinase
Increased creatine phosphokinase
Increased serum CK
Increased serum creatine kinase
Increased serum creatine phosphokinase
[ more ] 		0003236
Head tremor 0002346
Hypercholesterolemia
Elevated serum cholesterol
Elevated total cholesterol
Increased total cholesterol
[ more ] 		0003124
Hypoalbuminemia
Low blood albumin
0003073
Postural tremor 0002174
Strabismus
Squint eyes
Squint
Cross-eyed
[ more ] 		0000486
Urinary bladder sphincter dysfunction 0002839
1%-4% of people have these symptoms
Cerebellar atrophy
Degeneration of cerebellum
0001272
Chorea 0002072
Distal amyotrophy
Distal muscle wasting
0003693
Distal muscle weakness
Weakness of outermost muscles
0002460
Dysarthria
Difficulty articulating speech
0001260
Gait ataxia
Inability to coordinate movements when walking
0002066
Hyporeflexia
Decreased reflex response
Decreased reflexes
[ more ] 		0001265
Impaired distal tactile sensation
Decreased touch sensation in extremities
0006937
Impaired proprioception 0010831
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Peripheral axonal neuropathy 0003477
Pes cavus
High-arched foot
0001761
Scoliosis 0002650
Tremor 0001337
Percent of people who have these symptoms is not available through HPO
Abnormal pyramidal sign 0007256
Autosomal recessive inheritance 0000007
Chronic axonal neuropathy 0007267
Decreased motor nerve conduction velocity 0003431
Impaired distal vibration sensation 0006886
Increased circulating antibody level 0010702
Limb ataxia 0002070
Polyneuropathy
Peripheral nerve disease
0001271
Pontocerebellar atrophy 0006879
Progressive
Worsens with time
0003676
Progressive gait ataxia 0007240
Variable expressivity 0003828
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Last updated: 7/1/2020
Spinocerebellar ataxia with axonal neuropathy type 2 (SCAN2) is caused by changes (mutations) in the SETX gene, which provides instructions for making a protein that is involved in DNA repair. People with a mutation in SETX make a reduced amount of this important protein. This leads to an accumulation of damaged DNA which can cause cells to become unstable and die. Certain cells in the brain, such as those involved in coordinating movements (the cerebellum), appear to be most affected by cell death because these cells do not copy themselves to replace cells that have been lost. Scientists suspect that the loss of brain cells in the cerebellum causes the many signs and symptoms associated with SCAN2.[4]
Last updated: 6/2/2017
Spinocerebellar ataxia with axonal neuropathy type 2 is inherited in an autosomal recessive manner.[2] This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. Affected people inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:
  • 25% (1 in 4) chance to be affected
  • 50% (1 in 2) chance to be an unaffected carrier like each parent
  • 25% chance to be unaffected and not be a carrier
Last updated: 6/5/2017
A diagnosis of spinocerebellar ataxia with axonal neuropathy type 2 is often suspected based on the presence of characteristic signs and symptoms. Additional testing may then be ordered to confirm the diagnosis and to rule out other conditions that are associated with similar features. This testing may include:[5][2]
Last updated: 6/5/2017
Although there is no cure for spinocerebellar ataxia with axonal neuropathy type 2 (SCAN2), treatments are available to help manage the signs and symptoms of the condition. For example, affected people may benefit from physical therapy and speech therapy. A wheelchair or other devices may be necessary to help maintain mobility. Children with SCAN2 may also need additional help in school since they may have difficulties with reading, writing and other activities. In some cases, a low-cholesterol diet may be recommended.[2][6]
Last updated: 6/5/2017

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes Friedreich ataxia, ataxia with vitamin E deficiency, AOA1, ataxia-telangiectasia, ataxia-telangiectasia-like disorder, autosomal recessive spastic ataxia of Charlevoix-Saguenay.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

  • Coordination of Rare Diseases at Sanford (CoRDS) hosts a specific registry for patients with ataxia in partnership with the National Ataxia Foundation. The goal of the CoRDS registry is to connect as many patients and researchers as possible to help advance treatments and cures for rare diseases. The CoRDS registry is free for patients to enroll and for researchers to access.

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

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

  • Genetics Home Reference (GHR) contains information on Ataxia with Oculomotor Apraxia Type 2. This website is maintained by the National Library of Medicine.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • 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.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Pera J, Lechner S, Biskup S, Strach M, Grodzicki T, Slowik A. Two novel mutations of the SETX gene and ataxia with oculomotor apraxia type 2. Clin Neurol Neurosurg. January 2015; 128:44-46.
  2. Moreira MC & Koenig M. Ataxia with Oculomotor Apraxia Type 2. GeneReviews. 2018; https://www.ncbi.nlm.nih.gov/books/NBK1154.
  3. SPINOCEREBELLAR ATAXIA, AUTOSOMAL RECESSIVE 1. OMIM. August 2016; http://www.omim.org/entry/606002.
  4. ataxia with oculomotor apraxia. Genetics Home Reference. April 2015; https://ghr.nlm.nih.gov/condition/ataxia-with-oculomotor-apraxia.
  5. Mignarri A, Tessa A, Federico A, Santorelli FM, Dotti MT. Ataxia with oculomotor apraxia type 2: not always an easy diagnosis. Neurol Sci. August 2015; 36(8):1505-1507. https://www.ncbi.nlm.nih.gov/pubmed/25787807.
  6. Spinocerebellar ataxia with axonal neuropathy type 2. Orphanet. May 2015; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=64753.