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Disease Profile

Spinocerebellar ataxia 12

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 / 1 000 000

< 331

US Estimated

< 514

Europe Estimated

Age of onset

All ages

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ICD-10

G11.2

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)

SCA12; Spinocerebellar ataxia type 12

Categories

Congenital and Genetic Diseases; Nervous System Diseases

Summary

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

Orpha Number: 98762

Definition
Spinocerebellar ataxia type 12 (SCA12) is a very rare subtype of type I autosomal dominant cerebellar ataxia (ADCA type I; see this term). It is characterized by the presence of action tremor associated with relatively mild cerebellar ataxia. Associated pyramidal and extrapyramidal signs and dementia have been reported.

Epidemiology
Prevalence is unknown. Approximately 40 families have been reported.

Clinical description
The age of symptomatic onset ranges from 8 to 55 years with most patients presenting in the 4th decade.

Etiology
Like SCA8 the pathogenesis of SCA12 seems to be related to a toxic effect at the RNA level as it is caused by a CAG expansion at the 5' end of the PPP2R2B gene on chromosome 5q31-5q32.

Prognosis
Prognosis is essentially good. In many cases progression of the illness is slow and in general life expectancy is not affected.

Visit the Orphanet disease page for more resources.

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
30%-79% of people have these symptoms
Cerebellar atrophy
Degeneration of cerebellum
0001272
Cerebral atrophy
Degeneration of cerebrum
0002059
Hyperreflexia
Increased reflexes
0001347
Limb dysmetria
0002406
Parkinsonism
0001300
Tremor by anatomical site
Tremor of a body part
0030188
5%-29% of people have these symptoms
Abnormal pyramidal sign
0007256
Behavioral abnormality
Behavioral changes
Behavioral disorders
Behavioral disturbances
Behavioral problems
Behavioral/psychiatric abnormalities
Behavioural/Psychiatric abnormality
Psychiatric disorders
Psychiatric disturbances

[ more ]

0000708
Bradykinesia
Slow movements
Slowness of movements

[ more ]

0002067
Dementia
Dementia, progressive
Progressive dementia

[ more ]

0000726
Hypokinesia
Decreased muscle movement
Decreased spontaneous movement
Decreased spontaneous movements

[ more ]

0002375
Intention tremor
0002080
Poor fine motor coordination
0007010
Postural tremor
0002174
Sensorimotor neuropathy
Nerve damage causing decreased feeling and movement
0007141
Unsteady gait
Unsteady walk
0002317
Percent of people who have these symptoms is not available through HPO
Abnormality of eye movement
Abnormal eye movement
Abnormal eye movements
Eye movement abnormalities
Eye movement issue

[ more ]

0000496
Action tremor
0002345
Anxiety
Excessive, persistent worry and fear
0000739
Autosomal dominant inheritance
0000006
Axial dystonia
0002530
Cerebral cortical atrophy
Decrease in size of the outer layer of the brain due to loss of brain cells
0002120
Delusions
0000746
Depressivity
Depression
0000716
Dysarthria
Difficulty articulating speech
0001260
Dysdiadochokinesis
Difficulty performing quick and alternating movements
0002075
Dysmetria
Lack of coordination of movement
0001310
Facial myokymia
Involuntary facial quivering
0000317
Head tremor
0002346
Progressive cerebellar ataxia
0002073

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 12. Click on the link to view a sample search on this topic.