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Disease Profile

Spinocerebellar ataxia 17

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

G11.8

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)

SCA 17; Spinocerebellar ataxia type 17

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: 98759

Definition
Spinocerebellar ataxia type 17 (SCA17) is a rare subtype of type I autosomal dominant cerebellar ataxia (ADCA type I; see this term). It is characterized by a variable clinical picture which can include dementia, psychiatric disorders, parkinsonism, dystonia, chorea, spasticity, and epilepsy.

Epidemiology
Worldwide prevalence is unknown. Local prevalence is 0.47 per 1,000,000 in the Japanese population and 0.16 per 100,000 in North-East England. Fewer than 100 families have been reported to date.

Clinical description
Clinical features overlap with many neurodegenerative syndromes and specifically, Huntington disease (see this term).

Etiology
SCA17 is caused by a CAG repeat expansion in the TATA box-binding protein gene TBP (6q27).

Prognosis
Prognosis is poor. More than 60% of patients present with dysphagia which frequently results in aspiration and death. Mean disease duration is less than 18 years and a few patients live beyond 60 years of age.

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
80%-99% of people have these symptoms
Ataxia
0001251
Gait disturbance
Abnormal gait
Abnormal walk
Impaired gait

[ more ]

0001288
30%-79% of people have these symptoms
Abnormal pyramidal sign
0007256
Atrophy/Degeneration affecting the brainstem
0007366
Behavioral abnormality
Behavioral changes
Behavioral disorders
Behavioral disturbances
Behavioral problems
Behavioral/psychiatric abnormalities
Behavioural/Psychiatric abnormality
Psychiatric disorders
Psychiatric disturbances

[ more ]

0000708
Blepharospasm
Eyelid spasm
Eyelid twitching
Involuntary closure of eyelid
Spontaneous closure of eyelid

[ more ]

0000643
Cerebellar Purkinje layer atrophy
0012082
Chorea
0002072
Generalized cerebral atrophy/hypoplasia
Generalized cerebral degeneration/underdevelopment
0007058
Mental deterioration
Cognitive decline
Cognitive decline, progressive
Intellectual deterioration
Progressive cognitive decline

[ more ]

0001268
Neuronal loss in central nervous system
Loss of brain cells
0002529
Parkinsonism
0001300
Rigidity
Muscle rigidity
0002063
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
Torticollis
Wry neck
0000473
Writer's cramp
0002356
Percent of people who have these symptoms is not available through HPO
Aggressive behavior
Aggression
Aggressive behaviour
Aggressiveness

[ more ]

0000718
Apraxia
0002186
Autosomal dominant inheritance
0000006
Bradykinesia
Slow movements
Slowness of movements

[ more ]

0002067
Broad-based gait
Wide based walk
0002136
Cerebellar atrophy
Degeneration of cerebellum
0001272
Confusion
Disorientation
Easily confused
Mental disorientation

[ more ]

0001289
Depressivity
Depression
0000716
Diffuse cerebral atrophy
0002506
Dysarthria
Difficulty articulating speech
0001260
Dysmetria
Lack of coordination of movement
0001310
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

0002015
Dystonia
0001332
Frontal lobe dementia
0000727
Frontal release signs
0000743
Gait ataxia
Inability to coordinate movements when walking
0002066
Gaze-evoked nystagmus
0000640
Gliosis
0002171
Hallucinations
Hallucination
Sensory hallucination

[ more ]

0000738
Impaired pursuit initiation and maintenance
0007668
Intention tremor
0002080
Lack of insight
0000757
Limb ataxia
0002070
Mutism
Inability to speak
Muteness

[ more ]

0002300
Myoclonus
0001336
Paranoia
0011999
Positive Romberg sign
0002403
Progressive
Worsens with time
0003676
Seizure
0001250
Urinary incontinence
Loss of bladder control
0000020

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