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 21



Other Names:
SCA21; Spinocerebellar ataxia type 21
Categories:
This disease is grouped under:

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 98773

Definition
Spinocerebellar ataxia type 21 (SCA21) is a very rare subtype of type I autosomal dominant cerebellar ataxia (ADCA type I; see this term). It is characterized by slowly progressive cerebellar ataxia, mild cognitive impairment, postural and/or resting tremor, bradykinesia, and rigidity.

Epidemiology
Prevalence is unknown. Fewer than 20 cases in a 4-generation French family have been reported to date.

Clinical description
Mean age of onset is 17.4 years and is relatively early compared to most type I ADCAs. Individuals in successive generations tend to have earlier ages of onset. Parkinsonism was not responsive to L-dopa and magnetic resonance imaging (MRI) revealed cerebellar and brainstem atrophy.

Etiology
SCA21 maps to chromosome 7p21.3-p15.1 but the gene and gene mutation have not been identified.

Prognosis
There is insufficient clinical data to draw conclusions concerning prognosis.

Visit the Orphanet disease page for more resources.
Last updated: 5/1/2011

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 30 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormality of extrapyramidal motor function 0002071
Gait ataxia
Inability to coordinate movements when walking
0002066
Intermittent microsaccadic pursuits 0007944
Progressive cerebellar ataxia 0002073
30%-79% of people have these symptoms
Akinesia 0002304
Behavioral abnormality
Behavioral changes
Behavioral disorders
Behavioral disturbances
Behavioral problems
Behavioral/psychiatric abnormalities
Behavioural/Psychiatric abnormality
Psychiatric disorders
Psychiatric disturbances
[ more ]
0000708
Cerebellar vermis atrophy 0006855
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment
[ more ]
0100543
Dysarthria
Difficulty articulating speech
0001260
Dysgraphia 0010526
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Rigidity
Muscle rigidity
0002063
Tremor 0001337
5%-29% of people have these symptoms
Diplopia
Double vision
0000651
Percent of people who have these symptoms is not available through HPO
Aggressive behavior
Aggression
Aggressive behaviour
Aggressiveness
[ more ]
0000718
Apathy
Lack of feeling, emotion, interest
0000741
Autosomal dominant inheritance 0000006
Cerebellar atrophy
Degeneration of cerebellum
0001272
Cogwheel rigidity 0002396
Global developmental delay 0001263
Hyporeflexia
Decreased reflex response
Decreased reflexes
[ more ]
0001265
Impulsivity
Impulsive
0100710
Limb ataxia 0002070
Microsaccadic pursuit 0007792
Parkinsonism 0001300
Postural tremor 0002174
Scanning speech
Explosive speech
0002168
Slow progression
Signs and symptoms worsen slowly with time
0003677
Slow saccadic eye movements
Slow eye movements
0000514
Showing of 30 |
Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources


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

  • The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.

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

  • 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.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Spinocerebellar ataxia 21. 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.