Troyer syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Troyer syndrome is a type of hereditary spastic paraplegia, also called hereditary spastic paraparesis. Hereditary spastic paraplegias are a group of genetic disorders characterized by progressive stiffness (spasticity) and weakness of the leg muscles. The degree of leg weakness in people with hereditary spastic paraplegia can vary. Paraparesis is the term used to describe leg weakness, while paraplegia refers to severe weakness of the leg muscles.

Hereditary spastic paraplegias are divided into two types: pure and complex (sometimes called uncomplicated and complicated). The pure types of hereditary spastic paraplegia involve the legs and the bladder. Complex hereditary spastic paraplegias may include additional signs and symptoms such as intellectual disabilities, problems with coordination and balance (ataxia), and damage to the nerves that connect the brain and spinal cord to the rest of the body (peripheral neuropathy). Troyer syndrome is a complex hereditary spastic paraplegia.

People with Troyer syndrome can experience a variety of signs and symptoms. These health problems typically begin in early childhood and slowly worsen over time. Common features of Troyer syndrome include delays in learning to walk and talk, progressive weakness and spasticity of the leg muscles, muscle wasting in the hands and feet (distal amyotrophy), and short stature. Affected individuals may also have speech difficulties (dysarthria), skeletal (bone) abnormalities, and mood swings.

Troyer syndrome causes the breakdown (degeneration) and death of muscle cells and motor neurons (specialized nerve cells that control muscle movement) throughout a person's lifetime, leading to a slow decline in muscle and nerve function. Most affected individuals require wheelchair assistance by the time they are in their 50s or 60s. Troyer syndrome generally does not affect a person's life expectancy.

ORPHANET DEFINITION Autosomal recessive spastic paraplegia type 20 (SPG20) is a type of complex hereditary spastic paraplegia characterized by an onset in infancy of progressive spastic paraparesis associated with distal amyotrophy, psuedobulbar palsy, motor and cognitive delays, mild cerebellar signs (dysarthria, dysdiadochokinesia, mild intention tremor), short stature and subtle skeletal abnormalities (pes cavus, mild talipes equinovarus, kyphoscoliosis). SPG20 is due to mutations in the SPG20 gene (13q13.1), which encodes the protein spartin.

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Reported case(s): 36.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal cerebellum morphology · Frequent (79-30%)

Any structural abnormality of the cerebellum.

Abnormal foot morphology · Frequent (79-30%)

An abnormality of the skeleton of foot.

Abnormal hand morphology · Frequent (79-30%)

Any structural anomaly of the hand.

Abnormality of brain morphology · Frequent (79-30%)

A structural abnormality of the brain, which has as its parts the forebrain, midbrain, and hindbrain.

Abnormality of the hand · Frequent (79-30%)

An abnormality affecting one or both hands.

Abnormality of the skeletal system · Frequent (79-30%)

An abnormality of the skeletal system.

Babinski sign · Frequent (79-30%)

Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract.

Cognitive impairment · Frequent (79-30%)

Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering.

Constipation · Frequent (79-30%)

Infrequent or difficult evacuation of feces.

Delayed speech and language development · Frequent (79-30%)

A degree of language development that is significantly below the norm for a child of a specified age.

Dysarthria · Frequent (79-30%)

Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.

Dysphagia · Frequent (79-30%)

Difficulty in swallowing.

Dysuria · Frequent (79-30%)

Painful or difficult urination.

Generalized hypotonia · Frequent (79-30%)

Generalized muscular hypotonia (abnormally low muscle tone).

Other findings in the same source

From: Orphanet

Additional reported features include Global developmental delay (Frequent (79-30%)); Growth delay (Frequent (79-30%)); Hyperreflexia (Frequent (79-30%)); Hypertelorism (Frequent (79-30%)); Impaired vibratory sensation (Frequent (79-30%)); Joint hypermobility (Frequent (79-30%)); Motor delay (Frequent (79-30%)); Overbite (Frequent (79-30%)); Short stature (Frequent (79-30%)); Skeletal muscle atrophy (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Infancy

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Autosomal recessive

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Reported case(s): 36.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal recessive pattern usually involves disease-causing changes in both copies of a gene. Parents may each carry one altered copy without having the condition themselves. A genetic counsellor can explain carrier testing and reproductive implications using the actual laboratory findings, rather than the condition name alone.

Which doctor should you see?

The suggested department for discussing Troyer syndrome is Neurology, with a neurologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Troyer syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.