Autosomal dominant Charcot-Marie-Tooth disease type 2Z

What it is

From: Orphanet

A rare autosomal dominant hereditary axonal motor and sensory neuropathy characterized by early onset of generalized hypotonia and weakness, or later onset of distal lower limb muscle weakness and atrophy, cramps, and sensory impairment. Weakness and atrophy progress in an asymmetric fashion to involve also the proximal and upper limbs in the course of the disease. Additional features are pyramidal signs like increased muscle tone and extensor plantar reflexes, as well as learning difficulties.

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.

Distal lower limb amyotrophy · Very frequent (99-80%)

Muscular atrophy of distal leg muscles.

Distal lower limb muscle weakness · Very frequent (99-80%)

Reduced strength of the distal musculature of the legs.

Distal muscle weakness · Very frequent (99-80%)

Reduced strength of the musculature of the distal extremities.

Lower limb amyotrophy · Very frequent (99-80%)

Muscular atrophy affecting the lower limb.

Reduced tendon reflexes · Very frequent (99-80%)

A reduction (hyporeflexia) or complete absence (areflexia) of the involuntary muscle contraction normally elicited by a reflex stimulus, such as tapping a deep tendon.

Sensory axonal neuropathy · Very frequent (99-80%)

An axonal neuropathy of peripheral sensory nerves.

Abnormality of peripheral somatosensory evoked potentials · Very frequent (99-80%)

Mixed demyelinating and axonal polyneuropathy · Very frequent (99-80%)

Abnormal peripheral myelination · Frequent (79-30%)

An abnormality of the myelination of motor and sensory peripheral nerves. These are axons for motor nerves and dendrites for sensory nerves in the strict anatomic sense.

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.

Decreased distal sensory nerve action potential · Frequent (79-30%)

A reduction in the amplitude of sensory nerve action potential in distal nerve segments. This feature is measured by nerve conduction studies.

Difficulty running · Frequent (79-30%)

Reduced ability to run.

Distal amyotrophy · Frequent (79-30%)

Muscular atrophy affecting muscles in the distal portions of the extremities.

Fatigue · Frequent (79-30%)

A subjective feeling of tiredness characterized by a lack of energy and motivation.

Other findings in the same source

From: Orphanet

Additional reported features include Flexion contracture of finger (Frequent (79-30%)); Gait disturbance (Frequent (79-30%)); Impaired tactile sensation (Frequent (79-30%)); Impaired vibratory sensation (Frequent (79-30%)); Intellectual disability (Frequent (79-30%)); Joint contracture of the hand (Frequent (79-30%)); Motor axonal neuropathy (Frequent (79-30%)); Proximal upper limb amyotrophy (Frequent (79-30%)); Somatic sensory dysfunction (Frequent (79-30%)); Specific learning disability (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adolescent; Adult; Childhood; Infancy; Neonatal

Inheritance in the source

From: Orphanet

Autosomal dominant

Frequency and the population described

From: Orphanet

Reported case(s): 21.0; 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 dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Autosomal dominant Charcot-Marie-Tooth disease type 2Z 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 Autosomal dominant Charcot-Marie-Tooth disease type 2Z. 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.