Mitochondrial DNA-related cardiomyopathy and hearing loss

What it is

From: Orphanet

A rare mitochondrial disease that has a heterogeneous clinical presentation characterized by the association of progressive sensorineural hearing loss with hypertrophic cardiomyopathy and, in the majority of cases, encephalomyopathy symptoms such as ataxia, slurred speech, progressive external ophthalmoparesis (PEO), muscle weakness, myalgia, and exercise intolerance.

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.

Ataxia · Very frequent (99-80%)

Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

Gait disturbance · Very frequent (99-80%)

The term gait disturbance can refer to any disruption of the ability to walk.

Hypertrophic cardiomyopathy · Very frequent (99-80%)

Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.

Mild global developmental delay · Very frequent (99-80%)

A mild delay in the achievement of motor or mental milestones in the domains of development of a child.

Muscle weakness · Very frequent (99-80%)

Reduced strength of muscles.

Sensorineural hearing impairment · Very frequent (99-80%)

A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.

Slurred speech · Very frequent (99-80%)

Abnormal coordination of muscles involved in speech.

Abnormal cardiovascular system morphology · Frequent (79-30%)

Any structural anomaly of the heart and blood vessels.

Congestive heart failure · Frequent (79-30%)

The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction.

Dilated cardiomyopathy · Frequent (79-30%)

Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular dilatation and left ventricular systolic dysfunction in the absence of abnormal loading conditions (hypertension, valve disease) or coronary artery disease sufficient to cause global systolic impairment. Right ventricular dilation and dysfunction may be present but are not necessary for the diagnosis.

Dyspnea · Frequent (79-30%)

Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.

EMG abnormality · Frequent (79-30%)

Abnormal results of investigations using electromyography (EMG).

Encephalopathy · Frequent (79-30%)

Encephalopathy is a term that means brain disease, damage, or malfunction. In general, encephalopathy is manifested by an altered mental state.

Exercise intolerance · Frequent (79-30%)

A functional motor deficit where individuals whose responses to the challenges of exercise fail to achieve levels considered normal for their age and gender.

Other findings in the same source

From: Orphanet

Additional reported features include Increased circulating lactate concentration (Frequent (79-30%)); Increased circulating pyruvate concentration (Frequent (79-30%)); Lower limb pain (Frequent (79-30%)); Mental deterioration (Frequent (79-30%)); Ophthalmoparesis (Frequent (79-30%)); Progressive external ophthalmoplegia (Frequent (79-30%)); Ragged-red muscle fibers (Frequent (79-30%)); Chest pain (Occasional (29-5%)); Fatigue (Occasional (29-5%)); Febrile seizure (within the age range of 3 months to 6 years) (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adult; Childhood

Inheritance in the source

From: Orphanet

Mitochondrial inheritance

Frequency and the population described

From: Orphanet

Reported family(ies): 2.0; 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

Mitochondrial inheritance refers to changes in mitochondrial DNA, which is passed through egg cells. The pattern and expression of mitochondrial disease can be complex. Conditions involving mitochondrial function may also involve nuclear genes, so a specialist needs the exact molecular diagnosis before explaining family implications.

Which doctor should you see?

The suggested department for discussing Mitochondrial DNA-related cardiomyopathy and hearing loss is Cardiology, with a cardiologist 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.

• Is the main concern heart structure, rhythm, circulation or another cause?
• Which symptoms should change the timing of follow-up?
• How would a proposed investigation change the care plan?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Mitochondrial DNA-related cardiomyopathy and hearing loss. 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.