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 26


Other Names:
SCA26; Spinocerebellar ataxia type 26
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: 101112

Definition
A very rare subtype of autosomal dominant cerebellar ataxia type III (ADCA type III) characterized by late-onset and slowly progressive cerebellar signs (gait ataxia) and eye movement abnormalities.

Epidemiology
To date, only 23 affected patients have been described from one American family of Norwegian descent.

Clinical description
Spinocerebellar ataxia type 26 (SCA26) onset occurs between the ages of 26-60 with a mean age of onset of 42 years. Slowly progressive gait ataxia and dysarthria were reported in all patients. Nystagmus, impaired pursuit, and dysmetric saccades were described in majority of patitents. Left-sided pyramidal signs (hyperreflexia with positive Babinski sign) were reported in one patient. The disease duration is unknown.

Etiology
A candidate gene for SCA26 has recently been identified as the eukaryotic translation elongation factor 2 (EEF2) gene, located on chromosome 19p13.3. Further confirmatory studies are still required in order to determine if a mutation in this gene directly causes SCA26.

Diagnostic methods
Diagnosis is based on the clinical findings of pure cerebellar ataxia as well as molecular findings. Head magnetic resonance imaging (MRI) usually demonstrates the presence of atrophy of the cerebellum sparing the brainstem and is helpful in excluding other causes of ataxia. Molecular genetic testing identifies a mutation in the EEF2 gene, confirming a diagnosis of SCA26.

Differential diagnosis
Differential diagnoses include other forms of ADCA type III, in particular SCA5, SCA6, SCA11, SCA30 and SCA31.

Antenatal diagnosis
Antenatal diagnosis is possible in families with a known disease causing mutation.

Genetic counseling
SCA26 is inherited autosomal dominantly and genetic counseling is possible. Genetic counseling should be proposed to individuals having the disease-causing mutation informing them that there is 50% risk of passing the mutation to offspring.

Management and treatment
There is no cure for SCA26 and treatment is supportive. Neurological follow-up is recommended to monitor the progression of ataxia.

Prognosis
Disease progression is very slow, but precise prognosis is unknown.

Visit the Orphanet disease page for more resources.
Last updated: 12/1/2019

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.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Dysarthria
Difficulty articulating speech
0001260
Impaired horizontal smooth pursuit 0001151
Limb ataxia 0002070
Progressive cerebellar ataxia 0002073
Progressive gait ataxia 0007240
30%-79% of people have these symptoms
Cerebellar atrophy
Degeneration of cerebellum
0001272
Dysmetric saccades
Uncoordinated eye movement
0000641
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Truncal ataxia
Instability or lack of coordination of central trunk muscles
0002078
5%-29% of people have these symptoms
Babinski sign 0003487
Generalized hyperreflexia 0007034
Percent of people who have these symptoms is not available through HPO
Adult onset
Symptoms begin in adulthood
0003581
Autosomal dominant inheritance 0000006
Gait ataxia
Inability to coordinate movements when walking
0002066
Incoordination
Difficulties in coordination
Incoordination of limb movements
Limb incoordination
[ more ] 		0002311
Slow progression
Signs and symptoms worsen slowly with time
0003677
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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 26. Click on the link to view a sample search on this topic.

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