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Disease Profile

Spinocerebellar ataxia 13

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

US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


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.


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.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


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.


Not applicable


Other names (AKA)

SCA13; Spinocerebellar ataxia type 13


Congenital and Genetic Diseases; Nervous System Diseases


Spinocerebellar ataxia 13 (SCA13) is a rare sub-type of spinocerebellar ataxias (SCA), a group of neurological diseases that causes degeneration of the brain and spinal cord. The age when symptoms begin and the type and severity of symptoms of SCA13 can be different from person to person even in the same family. In almost every case, the disease progresses very slowly and does not affect a person's life span. Symptoms most commonly begin in early childhood or later in midlife, but can range from infancy to 60. The childhood forms is often least progressive, but may also include mild to moderate learning problems, taking longer to learn to crawl, walk, or run (delayed development of motor skills), and seizures. The main symptoms of SCA13 include difficulties coordinating movements (ataxia), especially walking; abnormal eye movements (nystagmus); mild to moderate intellectual disability; and involuntary muscle jerks or twitches (myoclonic jerks).[1][2][3][4] Other symptoms may include speech difficulty (dysarthria), difficulty eating (dysphagia), slowness of movements (bradykinesia), mild bladder problems, stiff and brisk deep tendon reflexes, and loss of the sense of vibration.[2][3]

SCA13 is caused by changes or mutations in the KCNC3 gene and it is inherited in an autosomal dominant manner. Since the symptoms of SCA13 can be similar to other types of SCA, genetic testing is used to confirm the diagnosis. In addition, unlike most of the other SCA's, a brain MRI will find loss of brain cells (neurons) in the part of the brain that helps control movement (cerebellum), but no noticeable loss of brain cells in the brain stem or the part of the brain important to higher levels of thinking (cerebral cortex).[3][4] Treatment may include anti-seizure medications, special assistance in school, speech therapy and communication devices, and/or, later in the disease, aids to help with walking such as a canes and walkers. Normal activity and exercise are recommended. Maintaining a healthy weight may help keep a person walking without assistance longer. The use of alcohol may increase the severity of the uncoordinated movements (ataxia).[3]


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:
30%-79% of people have these symptoms
Cerebellar atrophy
Degeneration of cerebellum
Difficulty running
Difficulty walking
Difficulty in walking
Difficulty articulating speech
Gait ataxia
Inability to coordinate movements when walking
Generalized hypotonia
Decreased muscle tone
Low muscle tone

[ more ]

Global developmental delay
Impaired distal vibration sensation
Impaired visuospatial constructive cognition
Intellectual disability, mild
Mental retardation, borderline-mild
Mild and nonprogressive mental retardation
Mild mental retardation

[ more ]

Limb ataxia
Motor delay
Involuntary, rapid, rhythmic eye movements
5%-29% of people have these symptoms
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

Hearing impairment
Hearing defect

[ more ]

Hyperactive deep tendon reflexes
Jerky ocular pursuit movements
Optic atrophy
Optic disc pallor
Postural instability
Balance impairment
Wry neck
Urinary incontinence
Loss of bladder control
Urinary urgency
Overactive bladder
1%-4% of people have these symptoms
Abnormal facial shape
Unusual facial appearance
Slow movements
Slowness of movements

[ more ]

Short stature
Decreased body height
Small stature

[ more ]

Upgaze palsy
Percent of people who have these symptoms is not available through HPO
Abnormal pyramidal sign
Autosomal dominant inheritance
Increased reflexes
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Limb dysmetria
Morphological abnormality of the pyramidal tract
Muscular hypotonia
Low or weak muscle tone
Progressive cerebellar ataxia
Slow progression
Signs and symptoms worsen slowly with time


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.


    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

      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

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


          1. Ataxia espinocerebelosa tipo 13. Orphanet. 2017; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Expert=98768&lng=ES.
          2. Subramony S, Advincula J, Perlman S et al. Comprehensive Phenotype of the p.Arg420his Allelic Form of Spinocerebellar Ataxia Type 13. 2013; 12(3):932-936. https://link.springer.com/article/10.1007%2Fs12311-013-0507-6.
          3. Stefan-M Pulst. Spinocerebellar Ataxia Type 13. GeneReviews. March 1, 2012; https://www.ncbi.nlm.nih.gov/books/NBK1225/.
          4. Montaut S, Apartis E, Chanson JB, Ewenczyk C, Renaud M, Guissart C, Muller J, Legrand AP, Durr A, Laugel V, Koenig M, Tranchant C, Anheim M. SCA13 causes dominantly inherited non-progressive myoclonus ataxia. Parkinsonism Relat Disord. May 2017; 38:80-84. https://www.ncbi.nlm.nih.gov/pubmed/28216058.