National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Spinocerebellar ataxia 2


Other Names:
SCA 2; Spinocerebellar ataxia type 2; Spinocerebellar atrophy 2; SCA 2; Spinocerebellar ataxia type 2; Spinocerebellar atrophy 2; Spinocerebellar ataxia Cuban type; Olivopontocerebellar atrophy 2; Spinocerebellar ataxia with slow eye movements; Wadia Swami syndrome; Spinocerebellar degeneration with slow eye movements; SDSEM; Olivopontocerebellar atrophy Holguin type See More
Categories:
This disease is grouped under:
Spinocerebellar ataxia 2 (SCA2) is a progressive disorder that causes symptoms including uncoordinated movement (ataxia), speech and swallowing difficulties, muscle wasting, slow eye movement, and sometimes dementia. Signs and symptoms usually begin in mid-adulthood but can appear any time from childhood to late-adulthood. SCA2 is caused by mutations in the ATXN2 gene and is inherited in an autosomal dominant manner.[1][2]
Last updated: 6/23/2014
Early symptoms of spinocerebellar ataxia may include uncoordinated movement (ataxia) and leg cramps. Other symptoms may include tremor; decreased muscle tone; poor tendon reflexes; abnormal eye movements; dementia; dystonia and/or chorea; muscle twitches; nerve irritation and swelling (polyneuropathy); leg weakness; difficulty swallowing; bladder dysfunction; and parkinsonism.[1][2]
Last updated: 1/31/2014

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 50 |
Medical Terms Other Names
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HPO ID
80%-99% of people have these symptoms
Abnormality of the substantia nigra 0045007
Progressive cerebellar ataxia 0002073
30%-79% of people have these symptoms
Abnormal cell morphology 0025461
Abnormality of the spinocerebellar tracts 0003133
Cerebellar Purkinje layer atrophy 0012082
Chorea 0002072
Dementia
Dementia, progressive
Progressive dementia
[ more ] 		0000726
Dysarthria
Difficulty articulating speech
0001260
Dystonia 0001332
Fasciculations
Muscle twitch
0002380
Gait ataxia
Inability to coordinate movements when walking
0002066
Generalized hypotonia
Decreased muscle tone
Low muscle tone
[ more ] 		0001290
Hyporeflexia
Decreased reflex response
Decreased reflexes
[ more ] 		0001265
Kinetic tremor 0030186
Muscle spasm 0003394
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Olivopontocerebellar hypoplasia 0006955
Postural tremor 0002174
Slow saccadic eye movements
Slow eye movements
0000514
Spinal cord posterior columns myelin loss 0008311
Supranuclear ophthalmoplegia 0000623
5%-29% of people have these symptoms
Abnormal cortical gyration 0002536
Cerebral cortical atrophy
Decrease in size of the outer layer of the brain due to loss of brain cells
0002120
Cerebral white matter atrophy 0012762
Hyperactive deep tendon reflexes 0006801
Parkinsonism 0001300
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Bradykinesia
Slow movements
Slowness of movements
[ more ] 		0002067
Dilated fourth ventricle 0002198
Distal amyotrophy
Distal muscle wasting
0003693
Dysdiadochokinesis
Difficulty performing quick and alternating movements
0002075
Dysmetria
Lack of coordination of movement
0001310
Dysmetric saccades
Uncoordinated eye movement
0000641
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty
[ more ] 		0002015
Gaze-evoked nystagmus 0000640
Genetic anticipation 0003743
Impaired horizontal smooth pursuit 0001151
Impaired vibratory sensation
Decreased vibration sense
Decreased vibratory sense
Diminished vibratory sense
Impaired vibratory sense
[ more ] 		0002495
Limb ataxia 0002070
Muscular hypotonia
Low or weak muscle tone
0001252
Myoclonus 0001336
Oculomotor apraxia 0000657
Olivopontocerebellar atrophy 0002542
Ophthalmoplegia
Eye muscle paralysis
0000602
Postural instability
Balance impairment
0002172
Rigidity
Muscle rigidity
0002063
Rod-cone dystrophy 0000510
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
Spinocerebellar tract degeneration 0002503
Urinary bladder sphincter dysfunction 0002839
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Last updated: 7/1/2020
Spinocerebellar ataxia 2 (SCA2) is inherited in an autosomal dominant manner. This means that having one changed (mutated) copy of ATXN2 (the responsible gene) in each cell is enough to cause signs and symptoms of the condition.[2]

The ATXN2 gene mutations that cause SCA2 involve a DNA sequence called a 'CAG trinucleotide repeat.' It is made up of a series of three DNA building blocks (CAG stands for cytosine, adenine, and guanine) that appear multiple times in a row. The CAG sequence is normally repeated about 22 times in the gene, but it can be repeated up to 31 times without causing health problems. SCA2 develops in people who have 32 or more CAG repeats in the ATXN2 gene.[2]

In most cases, an affected person inherits the mutated gene (with too many repeats) from an affected parent. However, in some cases, an affected person does not have an affected parent. People with an increased number of CAG repeats who don't develop SCA2 are still at risk of having children who will develop the disorder. This is because as the gene is passed down from parent to child, the number of CAG repeats often increases. In general, the more repeats a person has, the earlier symptoms begin. This phenomenon is called anticipation. People with 32 or 33 repeats tend to develop symptoms in late adulthood, while people with more than 45 repeats often have symptoms by their teens.  For some reason, the number of repeats tend to increase more when the gene is inherited from a person's father than when inherited from a person's mother.[2] Each child of an affected person has a 50% chance of inheriting the CAG repeat expansion.
Last updated: 6/24/2014
Molecular genetic testing (analysis of DNA) is needed for a diagnosis of spinocerebellar ataxia 2 (SCA2). This testing detects abnormal CAG trinucleotide repeat expansions in the ATXN2 gene. Affected people (or people who will later develop symptoms of SCA2) have a copy of the ATXN2 gene that has 33 or more CAG repeats. This testing detects nearly 100% of cases of SCA2.[1]

Last updated: 1/17/2017

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.
  • Spinocerebellar Ataxia: Making an Informed Choice about Genetic Testing is a booklet providing information about spinocerebellar ataxia and is available as a PDF document on the University of Washington Medical Center Web site. Click on the title above to view this resource.
Treatment of spinocerebellar ataxia 2 (SCA2) is supportive and aims to help the affected person maintain their independence and avoid injury. It is recommended that people with SCA2 remain physically active, maintain a healthy weight, use adaptive equipment as needed, and avoid alcohol and medications that affect cerebellar function. Adaptive equipment may include canes or other devices to help with walking and mobility. People with SCA2 may develop difficulty speaking and may need to use computerized devices or writing pads to help with communication. Levodopa may be prescribed to help with some of the movement problems (e.g., rigidity and tremor), and magnesium may improve muscle cramping.[1][3][4]
Last updated: 1/31/2014

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

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.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Spinocerebellar ataxia 2. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 

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

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Financial Resources

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

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.
  • MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
  • 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.
  • The Neuromuscular Disease Center at Washington University provides information about spinocerebellar ataxia 2.
  • 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.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Spinocerebellar ataxia 2. Click on the link to view a sample search on this topic.

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. Submit a new question

  • My father has been diagnosed with this condition. His condition has gotten progressively worse over the past 7-8 years. I am a 50 year old female and have shown no signs of this condition. I have two sons and am concerned about the possibility that they may have this condition in their genetic makeup. If this skips my generation, is it possible that they could have this later in life? See answer

  • What type of diet is recommended for people with spinocerebellar ataxia type 2? See answer

  • Is there a cure for spinocerebellar ataxia type 2? How can I learn more about clinical trials involving new treatments for spinocerebellar ataxia type 2? See answer


  1. Pulst SM. Spinocerebellar ataxia type 2. GeneReviews. November 12, 2015; http://www.ncbi.nlm.nih.gov/books/NBK1275/.
  2. Spinocerebellar ataxia type 2. Genetics Home Reference. February, 2011; http://ghr.nlm.nih.gov/condition/spinocerebellar-ataxia-type-2.
  3. Lastres-Becker I, Rüb U, Auburger G. Spinocerebellar ataxia 2 (SCA2). Cerebellum. 2008;
  4. Spinocerebellar degenerations. Neuromuscular Disease Center at Washington University. 2009; http://neuromuscular.wustl.edu/ataxia/domatax.html#sca2.