What is the DES Gene?

The DES gene provides instructions for making a protein called desmin. Desmin helps organize and stabilize heart muscle and skeletal muscle cells, allowing them to withstand repeated contraction and relaxation.

Certain disease-causing DES variants are associated with inherited cardiomyopathy, heart-rhythm and electrical-conduction problems, and skeletal-muscle disease. These conditions are sometimes described as DES-related disease, desminopathy, or desmin-related myopathy.

Not every change in the DES gene causes disease. The possible health effects depend on the specific variant, its classification, and a person’s medical and family history.

What does a DES variant mean?

A DES gene variant, more accurately called a DES genetic variant, is a change in the DNA sequence of the DES gene. A genetic-testing laboratory may classify a variant as pathogenic, likely pathogenic, uncertain, likely benign, or benign.

A pathogenic or likely pathogenic DES variant may help explain cardiomyopathy, abnormal heart rhythms, cardiac conduction disease, or muscle weakness. A variant of uncertain significance does not provide enough evidence to confirm or exclude a diagnosis.

A genetic counselor or cardiovascular-genetics specialist can explain what your result means in the context of your symptoms, heart testing, family history, and the specific variant identified.

Can a DES variant cause cardiomyopathy?

Yes. Pathogenic and likely pathogenic DES variants are established causes of genetic cardiomyopathy. Dilated cardiomyopathy is a well-recognized presentation, but DES variants have also been associated with restrictive cardiomyopathy, arrhythmogenic cardiomyopathy, and other cardiomyopathy patterns.

The effects can vary considerably. Some people develop heart-muscle disease, some primarily develop electrical or rhythm abnormalities, and others have both cardiac and skeletal-muscle involvement. Symptoms and age of onset can differ even among relatives who carry the same DES variant.

What is DES-related cardiomyopathy?

DES-related cardiomyopathy is a form of genetic heart disease associated with a pathogenic or likely pathogenic DES variant. Depending on the individual, the heart muscle may become enlarged, weakened, stiff, or show areas of fibrosis on cardiac imaging.

DES-related heart disease may also affect the heart’s electrical system. Some people develop slow heart rhythms, heart block, atrial arrhythmias, or ventricular arrhythmias before significant weakness of the heart muscle is detected. This is one reason ongoing cardiac and heart-rhythm monitoring may be important.

Can DES variants cause heart-rhythm or conduction problems?

Yes. Cardiac conduction disease and abnormal heart rhythms are important features of DES-related disease. The electrical signals controlling the heartbeat may travel too slowly or become blocked, sometimes causing an unusually slow heartbeat.

Pathogenic or likely pathogenic DES variants may also be associated with atrial or ventricular arrhythmias. Possible warning signs include palpitations, dizziness, unexplained fainting, or near-fainting. Some rhythm abnormalities cause no noticeable symptoms and are discovered during an electrocardiogram or ambulatory heart-rhythm monitor.

Seek urgent medical care for fainting during physical activity, sustained palpitations accompanied by dizziness, severe shortness of breath, chest pain, or other symptoms that could represent a serious heart problem.

What is desmin-related myopathy or desminopathy?

Desmin-related myopathy is a muscle disorder caused by certain disease-causing DES variants. It is generally classified as a type of myofibrillar myopathy (muscle weakness disorder) and may also be called desminopathy.

The condition can cause progressive weakness in the legs, feet, hands, arms, trunk, or other skeletal muscles. In some people, muscles involved in swallowing or breathing may also be affected. Heart disease may occur before, after, or at the same time as skeletal-muscle symptoms.

Not everyone with a pathogenic or likely pathogenic DES variant develops muscle weakness. Some people have primarily cardiac disease, while others have both heart and muscle involvement.

What symptoms can be associated with a DES variant?

Symptoms vary according to the specific DES variant and the parts of the body affected. Possible heart-related symptoms include:

• Shortness of breath, especially during activity or when lying down
• Fatigue or reduced exercise tolerance
• Swelling in the legs, ankles, or feet
• A fast, slow, irregular, or pounding heartbeat
• Dizziness, fainting, or near-fainting
• Chest discomfort

Possible neuromuscular symptoms include:

• Progressive weakness in the legs, feet, hands, or arms
• Difficulty walking, climbing stairs, or rising from a chair
• Frequent falls or changes in balance
• Muscle pain
• Joint stiffness or contractures
• Difficulty swallowing
• Breathing difficulty or reduced respiratory function caused by respiratory-muscle weakness

These symptoms have many possible causes. A healthcare professional can determine whether cardiac, neurological, or respiratory evaluation is appropriate.

How is DES-related cardiomyopathy diagnosed?

Evaluation usually begins with a personal and family medical history and a physical examination. Cardiac testing may include:

• An electrocardiogram, or ECG
• An echocardiogram
• Cardiac MRI
• Ambulatory heart-rhythm monitoring
• Exercise testing or other tests recommended by the care team

Genetic testing is one part of the diagnostic process. A DES genetic result should be interpreted alongside heart imaging, rhythm testing, symptoms, and family history.

If muscle weakness, swallowing problems, or respiratory symptoms are present, evaluation by a neurologist or neuromuscular specialist may also be appropriate. Additional testing may include a muscle-strength assessment, electromyography, respiratory-function testing, or other studies selected for the individual.

Should family members get DES genetic testing?

If you have a pathogenic or likely pathogenic DES variant, a genetic counselor may recommend targeted testing for certain biological relatives.

Many disease-causing DES variants follow an autosomal dominant inheritance pattern. When a person has a DES variant, each biological child has a 50% chance of inheriting that variant. The risk for parents, siblings, and other relatives depends on whether the variant was inherited or occurred as a new genetic change (referred to as de novo). Rare recessive forms of DES-related disease have also been reported, meaning an individual needs two DES variants to have DES-related disease.

Targeted testing can identify relatives who may benefit from cardiac screening and those who did not inherit the known familial variant. Relatives should receive genetic counseling so they understand the possible benefits, limitations, and purpose of testing.

If a pathogenic or likely pathogenic variant has not been identified in a family—or if the only finding is a variant of uncertain significance—relatives may still need clinical cardiac screening based on their family history. A negative genetic test does not always eliminate the need for screening unless an individual tests negative for a known pathogenic or likely pathogenic variant in their family member with DES-related disease.

What heart monitoring may be recommended for someone with a DES variant?

Monitoring depends on the variant classification, age, symptoms, family history, and whether cardiomyopathy or an electrical abnormality has already been detected. A care team may recommend periodic:

• Visits with a cardiologist
• Electrocardiograms
• Echocardiograms
• Cardiac MRI scans
• Ambulatory heart-rhythm monitoring

Because DES-related disease can affect the heart’s electrical system, rhythm monitoring may be important even when the heart’s pumping function appears normal. People with skeletal-muscle symptoms may also need neuromuscular or respiratory follow-up.

There is no single monitoring schedule for everyone with a DES variant. An inherited-cardiomyopathy specialist can create an individualized plan based on the person’s genetic result, symptoms, family history, and clinical findings.

What if my DES genetic test shows a variant of uncertain significance?

A variant of uncertain significance, or VUS, means there is not currently enough evidence to determine whether a particular DES change causes disease.

A DES VUS should not generally be used by itself to diagnose DES-related cardiomyopathy, make major medical decisions, or conduct genetic testing in unaffected relatives. Medical care should instead be guided by symptoms, heart testing, muscle findings, and family history.

Variant classifications can change as new evidence becomes available. Staying in contact with the ordering provider or genetic counselor can help ensure that you learn about any future classification changes.

How can I live well with a DES variant?

Living well with a pathogenic or likely pathogenic DES variant may involve regular heart and heart-rhythm evaluations, taking prescribed medications, and reporting new or changing symptoms promptly. People with muscle or respiratory involvement may also benefit from care coordinated with neurology, physical therapy, pulmonology, or other specialists.

Ask your care team about:

• Safe and appropriate physical activity
• Heart-failure and blood-pressure management
• Symptoms that require urgent evaluation
• Pregnancy and reproductive planning
• Whether neuromuscular or respiratory testing is appropriate

Your care plan should be based on your specific variant, medical findings, symptoms, and family history—not solely on the presence of a genetic change.

Why should I join the DES community?

The DES community connects people living with a DES variant, DES-related cardiomyopathy, or desmin-related myopathy, along with their relatives and caregivers.

Joining can provide opportunities to ask questions, share experiences, and connect with people who understand the challenges of a rare genetic heart and muscle condition. Community members may also receive information about DES research, clinical trials, educational resources, and opportunities to participate in research.

Join the DES community by signing up for the mailing list for DES genetics, cardiomyopathy, and research information.

Is the DES community only for people with cardiomyopathy?

No. The DES community may also be helpful for people who:

• Carry a DES variant but do not currently have symptoms
• Have desmin-related myopathy or another neuromuscular presentation
• Are seeking more information about a genetic result
• Have a relative with a DES variant
• Provide care or support to someone affected by DES-related disease

You do not need to have cardiomyopathy—or have all the answers—before joining.