Autosomal dominant Charcot-Marie-Tooth disease type 2A2

What it is

From: Orphanet

A subtype of Autosomal dominant Charcot-Marie-Tooth disease type 2 characterized by the childhood onset of distal weakness and areflexia (with earlier and more severe involvement of the lower extremities), reduced sensory modalities (primarily pain and temperature sensation), foot deformities, postural tremor, scoliosis and contractures. Optic atrophy, vocal cord palsy with dysphonia, sensorineural hearing loss, spinal cord abnormalities and hydrocephalus have also been reported.

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 foot morphology · Very frequent (99-80%)

An abnormality of the skeleton of foot.

Absent Achilles reflex · Very frequent (99-80%)

Absence of the Achilles reflex (also known as the ankle jerk reflex), which can normally be elicited by tapping the tendon is tapped while the foot is dorsiflexed.

EMG: chronic denervation signs · Very frequent (99-80%)

Evidence of chronic denervation on electromyography.

Foot dorsiflexor weakness · Very frequent (99-80%)

Weakness of the muscles responsible for dorsiflexion of the foot, that is, of the movement of the toes towards the shin. The foot dorsiflexors include the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the peroneus tertius muscles.

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

An axonal neuropathy of peripheral sensory nerves.

Somatic sensory dysfunction · Very frequent (99-80%)

An abnormality of the primary sensation that is mediated by peripheral nerves (pain, temperature, touch, vibration, joint position). The word hypoesthesia (or hypesthesia) refers to a reduction in cutaneous sensation to a specific type of testing.

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

An abnormality affecting one or both hands.

Areflexia of lower limbs · Frequent (79-30%)

Inability to elicit tendon reflexes in the lower limbs.

Difficulty climbing stairs · Frequent (79-30%)

Reduced ability to climb stairs.

Difficulty running · Frequent (79-30%)

Reduced ability to run.

Distal lower limb muscle weakness · Frequent (79-30%)

Reduced strength of the distal musculature of the legs.

Distal sensory impairment · Frequent (79-30%)

An abnormal reduction in sensation in the distal portions of the extremities.

Foot pain · Frequent (79-30%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the foot.

Hand muscle weakness · Frequent (79-30%)

Reduced strength of the musculature of the hand.

Other findings in the same source

From: Orphanet

Additional reported features include Hand tremor (Frequent (79-30%)); Impaired pain sensation (Frequent (79-30%)); Impaired temperature sensition (Frequent (79-30%)); Impaired vibratory sensation (Frequent (79-30%)); Increased laxity of ankles (Frequent (79-30%)); Muscle spasm (Frequent (79-30%)); Pes cavus (Frequent (79-30%)); Poor fine motor coordination (Frequent (79-30%)); Frequent falls (Frequent (79-30%)); Paresis of extensor muscles of the big toe (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Childhood

Inheritance in the source

From: Orphanet

Autosomal dominant

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 2A2 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 2A2. 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.