Rare Immunology News

Disease Profile

Troyer syndrome

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

Infancy

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ICD-10

G11.4

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.

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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)

SPG20; Spastic paraparesis, childhood-onset, with distal muscle wasting; Spastic paraplegia, autosomal recessive, Troyer type;

Categories

Congenital and Genetic Diseases; Musculoskeletal Diseases; Nervous System Diseases

Summary

Troyer syndrome is a neurological disorder and one of the many types of hereditary spastic paraplegia.[1][2] Signs and symptoms typically begin in early childhood and may include progressive muscle weakness and stiffness (spasticity) in the legs; muscle wasting in the hands and feet; paraplegia; leg contractures; developmental delays; speech difficulty; mood swings; and short stature.[2][3][1] Symptoms worsen over time, with most people needing a wheelchair by their 50s or 60s.[1][2] Life expectancy is normal.[3] Troyer syndrome is caused by mutations in the SPG20 gene and is inherited in an autosomal recessive manner.[2][3] Treatment is symptomatic and supportive.[1]

Symptoms

The signs and symptoms of Troyer syndrome can vary, and some people are more severely affected than others.[1] Symptoms typically begin in early childhood. Most affected children have delays in walking and talking, followed by slow deterioration in both manner of walking (gait) and speech.[3] Affected people have progressive muscle weakness and stiffness (spasticity) in the legs; muscle wasting in the hands and feet; paraplegia; leg contractures; learning disorders; and short stature.[2][3][1] Mood swings and mood disorders, causing inappropriate euphoria and/or crying, are common.[3]

Other features can include drooling; exaggerated reflexes (hyperreflexia) in the legs; uncontrollable movements of the arms and legs (choreoathetosis); skeletal abnormalities; and a bending outward (valgus) of the knees.[2][1]

There is generally a slow, progressive decline in muscle and nerve function, and symptoms worsen over time. Most people need a wheelchair by their 50s or 60s.[1][2] Affected people typically have a normal life expectancy.[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:
HPO ID
30%-79% of people have these symptoms
Abnormal cerebellum morphology
Abnormality of the cerebellum
Cerebellar abnormalities
Cerebellar abnormality
Cerebellar anomaly

[ more ]

0001317
Abnormal hand morphology
Abnormal shape of hand
0005922
Babinski sign
0003487
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment

[ more ]

0100543
Constipation
0002019
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
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty

[ more ]

0002015
Dysuria
Painful or difficult urination
0100518
Generalized hypotonia
Decreased muscle tone
Low muscle tone

[ more ]

0001290
Global developmental delay
0001263
Hypertelorism
Wide-set eyes
Widely spaced eyes

[ more ]

0000316
Impaired vibratory sensation
Decreased vibration sense
Decreased vibratory sense
Diminished vibratory sense
Impaired vibratory sense

[ more ]

0002495
Joint hypermobility
Double-Jointed
Flexible joints
Increased mobility of joints

[ more ]

0001382
Motor delay
0001270
Overbite
0011094
Short stature
Decreased body height
Small stature

[ more ]

0004322
Slurred speech
0001350
Spastic dysarthria
0002464
Spastic paraparesis
0002313
Specific learning disability
0001328
Upper limb muscle weakness
Decreased arm strength
Weak arm

[ more ]

0003484
5%-29% of people have these symptoms
Abnormal thumb morphology
Abnormality of the thumb
Abnormality of the thumbs
Thumb deformity

[ more ]

0001172
Abnormality of the nares
Abnormality of the nostrils
0005288
Ankle clonus
Abnormal rhythmic movements of ankle
0011448
Anxiety
Excessive, persistent worry and fear
0000739
Clinodactyly
Permanent curving of the finger
0030084
Distal amyotrophy
Distal muscle wasting
0003693
Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
0000494
Emotional lability
Emotional instability
0000712
Epicanthus
Eye folds
Prominent eye folds

[ more ]

0000286
Genu valgum
Knock knees
0002857
Hallucinations
Hallucination
Sensory hallucination

[ more ]

0000738
Hoarse voice
Hoarseness
Husky voice

[ more ]

0001609
Low-set ears
Low set ears
Lowset ears

[ more ]

0000369
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference

[ more ]

0000252
Occasional neurofibromas
0009595
Panic attack
0025269
Pes cavus
High-arched foot
0001761
Prominent nose
Big nose
Disproportionately large nose
Increased nasal size
Increased size of nose
Large nose
Pronounced nose

[ more ]

0000448
Psychosis
0000709
Sleep disturbance
Difficulty sleeping
Trouble sleeping

[ more ]

0002360
Spastic gait
Spastic walk
0002064
Speech apraxia
0011098
1%-4% of people have these symptoms
Ataxia
0001251
Bilateral vestibular Schwannoma
0009589
Cafe-au-lait spot
0000957
Cortical cataract
0100019
Ependymoma
0002888
Hearing impairment
Deafness
Hearing defect

[ more ]

0000365
Hydronephrosis
0000126
Juvenile posterior subcapsular lenticular opacities
0007935
Meningioma
0002858
Retinal hamartoma

Cause

Troyer syndrome is caused by mutations in the SPG20 gene.[2][3] This gene gives the body instructions to make a protein called spartin, which is present in many body tissues, including those of the nervous system. However, the function of this protein is not fully understood. It is thought to play various roles needed for the functions of cells.[2][3] Troyer syndrome is assumed to be caused by a loss of function of the spartin protein. More research on the normal functions of the spartin protein is needed to better understand exactly how mutations in the SPG20 gene cause the features of Troyer syndrome.[3]

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.

    Treatment

    There are currently no treatments known to prevent or slow the progression of Troyer syndrome.[1] Treatment aims to relieve symptoms of the disease and improve quality of life.

    Treatment for spasticity involves both exercise and medication, especially baclofen (Lioresal®), which is used either orally or by intrathecal pump. Tizanidine, dantrolene (with precautions), and Botox® have also been useful in reducing muscle spasticity. Daily physical therapy is recommended.[3]

    Treatment may also include:

    • Occupational therapy, assistive walking devices, and ankle-foot orthotics as needed
    • Oxybutynin to reduce urinary urgency
    • Antidepressants or mood stabilizers to manage emotional or mood disorders[3]

    Additional information about the management of Troyer syndrome can be viewed on the GeneReviews Web site.

    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

      Social Networking Websites

      • RareConnect is an online social network for patients and families to connect with one another and share their experience living with a rare disease. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders). Click on the link above to view the community for Hereditary spastic paraplegia.

      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.
        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • 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 Troyer syndrome. Click on the link to view a sample search on this topic.

          References

          1. Troyer Syndrome Information Page. NINDS. January 3, 2012; https://www.ninds.nih.gov/disorders/troyer_syndrome/troyer_syndrome.htm.
          2. Troyer syndrome. Genetics Home Reference. January, 2008; https://ghr.nlm.nih.gov/condition/troyer-syndrome.
          3. Patel H, Harlalka G & Crosby A. Troyer syndrome. GeneReviews. August 4, 2011; https://www.ncbi.nlm.nih.gov/books/NBK1382/.

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