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Disease Profile

Spinocerebellar ataxia 3

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.
1-9 / 100 000

3,310 - 29,790

US Estimated

1-9 / 100 000

5,135 - 46,215

Europe Estimated

Age of onset

Childhood

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ICD-10

G11.8

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.

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)

SCA3; Machado-Joseph disease; MJD;

Categories

Nervous System Diseases

Summary

Spinocerebellar ataxia 3 (SCA3) is a rare, inherited form of ataxia. Signs and symptoms may begin between childhood and late adulthood and vary greatly. Symptoms may include slowly progressive clumsiness in the arms and legs; a manner of walking (gait) that may be mistaken for drunkenness; difficulty speaking and swallowing; impaired eye movements or vision; and lower limb spasticity. Some people with SCA3 develop dystonia or symptoms similar to those of Parkinson’s disease; twitching of the face or tongue; nerve damage (neuropathy); or problems with urination and the autonomic nervous system.[1]

SCA3 is caused by a mutation in the ATXN3 gene and inheritance is autosomal dominant. There is no medication that slows the progressive course of the disease; management aims to relieve some symptoms and improve quality of life.[2] Life expectancy ranges from the mid-30s for those with the most severe forms, to a nearly normal life expectancy for those with milder forms.[1]

Symptoms

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
Abnormal pyramidal sign
0007256
Abnormality of extrapyramidal motor function
0002071
Clumsiness
0002312
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

0000750
Diplopia
Double vision
0000651
Dysarthria
Difficulty articulating speech
0001260
Dystonia
0001332
Hyperreflexia
Increased reflexes
0001347
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Progressive cerebellar ataxia
0002073
Progressive external ophthalmoplegia
0000590
Proptosis
Bulging eye
Eyeballs bulging out
Prominent eyes
Prominent globes
Protruding eyes

[ more ]

0000520
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting

[ more ]

0003202
5%-29% of people have these symptoms
Abnormal autonomic nervous system physiology
0012332
Abnormality of temperature regulation
Poor temperature regulation
0004370
Vestibular dysfunction
0001751
Vocal cord paralysis
Inability to move vocal cords
0001605
1%-4% of people have these symptoms
Ataxia
0001251
External ophthalmoplegia
Paralysis or weakness of muscles within or surrounding outer part of eye
0000544
Fasciculations
Muscle twitch
0002380
Gaze-evoked nystagmus
0000640
Parkinsonism
0001300
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
Percent of people who have these symptoms is not available through HPO
Abnormal electrooculogram
0030454
Absent Achilles reflex
Absent ankle reflexes
0003438
Autosomal dominant inheritance
0000006
Babinski sign
0003487
Bradykinesia
Slow movements
Slowness of movements

[ more ]

0002067
Cerebellar atrophy
Degeneration of cerebellum
0001272
Chronic pain
Long-lasting pain
0012532
Dementia
Dementia, progressive
Progressive dementia

[ more ]

0000726
Dilated fourth ventricle
0002198
Distal amyotrophy
Distal muscle wasting
0003693
Dysmetric saccades
Uncoordinated eye movement
0000641
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

0002015
Facial-lingual fasciculations
0007089
Genetic anticipation
0003743
Gliosis
0002171
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
Muscle spasm
0003394
Postural instability
Balance impairment
0002172
Progressive
Worsens with time
0003676
Ptosis
Drooping upper eyelid
0000508
Rigidity
Muscle rigidity
0002063
Spinocerebellar tract degeneration
0002503
Supranuclear ophthalmoplegia
0000623
Truncal ataxia
Instability or lack of coordination of central trunk muscles
0002078
Urinary bladder sphincter dysfunction
0002839

Diagnosis

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

  • 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.
  • 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.

    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

      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

        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.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Spinocerebellar ataxia 3. Click on the link to view a sample search on this topic.

          References

          1. Machado-Joseph Disease Fact Sheet. National Institute of Neurological Disorders and Stroke Website. April 16, 2014; https://www.ninds.nih.gov/disorders/machado_joseph/detail_machado_joseph.htm.
          2. Henry Paulson. Spinocerebellar Ataxia Type 3. GeneReviews. September 24, 2015; https://www.ncbi.nlm.nih.gov/books/NBK1196/.