Early-onset myopathy with fatal cardiomyopathy

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Early-onset myopathy with fatal cardiomyopathy (EOMFC) is an inherited muscle disease that affects the skeletal muscles, which are used for movement, and the heart (cardiac) muscle. This condition is characterized by skeletal muscle weakness that becomes apparent in early infancy. Affected individuals have delayed development of motor skills, such as sitting, standing, and walking. Beginning later in childhood, people with EOMFC may also develop joint deformities called contractures that restrict the movement of the neck and back. Scoliosis, which is an abnormal side-to-side curvature of the spine, also develops in late childhood.

A form of heart disease called dilated cardiomyopathy is another feature of EOMFC. Dilated cardiomyopathy enlarges and weakens the cardiac muscle, preventing the heart from pumping blood efficiently. Signs and symptoms of this condition can include an irregular heartbeat (arrhythmia), shortness of breath, extreme tiredness (fatigue), and swelling of the legs and feet. The heart abnormalities associated with EOMFC usually become apparent in childhood, after the skeletal muscle abnormalities. The heart disease worsens quickly, and it often causes heart failure and sudden death in adolescence or early adulthood.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

EOMFC is caused by variants (also known as mutations) in the TTN gene. This gene provides instructions for making a protein called titin, which plays an important role in skeletal and cardiac muscle function.

Within muscle cells, titin is an essential component of structures called sarcomeres and is critical for muscles to tense (contract) normally . Sarcomeres are the basic units of muscle contraction; they are made of proteins that generate the mechanical force needed for muscles to contract. Titin has several functions within sarcomeres. One of this protein's most important jobs is to provide structure, flexibility, and stability to these cell structures. Titin also plays a role in chemical signaling and in assembling new sarcomeres.

The TTN gene variants involved in EOMFC lead to the production of an abnormally short version of titin. The abnormal protein disrupts the function of sarcomeres, which prevents skeletal and cardiac muscle from contracting normally. These muscle abnormalities underlie the features of EOMFC, including skeletal muscle weakness and dilated cardiomyopathy.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have variants. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

EOMFC appears to be a rare disorder, although its prevalence is unknown. It has been reported in a small number of families of Moroccan and Sudanese descent.

Understanding terms used in the source

These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.

Dilated cardiomyopathy

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.

Death in adolescence

Death during adolescence, the period between childhood and adulthood (roughly between the ages of 10 and 16 years).

Cardiomyopathy

A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.

Arrhythmia

Any cardiac rhythm other than the normal sinus rhythm. Such a rhythm may be either of sinus or ectopic origin and either regular or irregular. An arrhythmia may be due to a disturbance in impulse formation or conduction or both.

Affected

This term applies to a family member who is diagnosed with the same condition as the individual who is the primary focus of investigation (the proband).

Which doctor should you see?

The suggested department for discussing Early-onset myopathy with fatal cardiomyopathy 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 Early-onset myopathy with fatal cardiomyopathy. 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.

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.