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Myofibrillar Myopathy

Table of Contents

Myofibrillar Myopathy

MFM

Myofibrilar myopathy (MFM) is a neuromuscular disease characterized by slowly progressive muscle weakness that can involve both proximal muscles (such as hips and shoulders) and distal muscles (those further away from the trunk). Explore symptoms, causes, and genetics of this rare condition.

Neuromuscular Junction

Image by TheVisualMD

About

Myofibrillary myopathy histology

Image by Luo Y-B, Peng Y, Lu Y, Li Q, Duan H, Bi F and Yang H/Wikimedia

Myofibrillary myopathy histology

(A) HE stain in BAG3opathy showing intramuscular eosinophilic deposits (B-D) Immunohistochemial stains (respectively: desmin, BAG3 αB crystallin) on serial sections showing MFM-protein accumulation. (E) HE stain in filaminopathy showing fiber size variation and rare regeneration. (F) HE stain in FHL1opathy showing eosinophilic material and small fiber size. (G) HE stain in HMERF showing vacuolated fibers (arrow), central nucleated fibers, and nuclear clumps. (H) Gomori stain showing necklace cytoplasmic bodies. (I) HE in titinopathy showing central nuclei and selective type 1 atrophy. (J) NADH stain in same titinopathy patient. (K) HE in titinopathy showing rimmed vacuoles (arrow) and esosinophilic bodies (arrowhead). (L) NADH in same titinopathy patient, showing occasional bar-like enzyme aggregation (arrow). Magnification 200x

Image by Luo Y-B, Peng Y, Lu Y, Li Q, Duan H, Bi F and Yang H/Wikimedia

What Is Myofibrillar Myopathy?

Myofibrillar myopathy is part of a group of disorders called muscular dystrophies that affect muscle function and cause weakness. Myofibrillar myopathy primarily affects skeletal muscles, which are muscles that the body uses for movement. In some cases, the heart (cardiac) muscle is also affected.

The signs and symptoms of myofibrillar myopathy vary widely among affected individuals, typically depending on the condition's genetic cause. Most people with this disorder begin to develop muscle weakness (myopathy) in mid-adulthood. However, features of this condition can appear anytime between infancy and late adulthood. Muscle weakness most often begins in the hands and feet (distal muscles), but some people first experience weakness in the muscles near the center of the body (proximal muscles). Other affected individuals develop muscle weakness throughout their body. Facial muscle weakness can cause swallowing and speech difficulties. Muscle weakness worsens over time.

Other signs and symptoms of myofibrillar myopathy can include a weakened heart muscle (cardiomyopathy), muscle pain (myalgia), loss of sensation and weakness in the limbs (peripheral neuropathy), and respiratory failure. Individuals with this condition may have skeletal problems including joint stiffness (contractures) and abnormal side-to-side curvature of the spine (scoliosis). Rarely, people with this condition develop clouding of the lens of the eyes (cataracts).

Source: MedlinePlus Genetics

Causes

Mutation

Image by National Human Genome Research Institute (NHGRI)

Mutation

A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.

Image by National Human Genome Research Institute (NHGRI)

What Causes Myofibrillar Myopathy?

Mutations in several genes can cause myofibrillar myopathy. These genes provide instructions for making proteins that play important roles in muscle fibers. Within muscle fibers, these proteins are involved in the assembly of structures called sarcomeres. Sarcomeres are necessary for muscles to tense (contract). The proteins associated with myofibrillar myopathy are normally active on rod-like structures within the sarcomere called Z-discs. Z-discs link neighboring sarcomeres together to form myofibrils, the basic unit of muscle fibers. The linking of sarcomeres and formation of myofibrils provide strength for muscle fibers during repeated muscle contraction and relaxation.

Gene mutations that cause myofibrillar myopathy disrupt the function of skeletal and cardiac muscle. Various muscle proteins form clumps (aggregates) in the muscle fibers of affected individuals. The aggregates prevent these proteins from functioning normally, which reduces linking between neighboring sarcomeres. As a result, muscle fiber strength is diminished.

At least six genes have been associated with myofibrillar myopathy. Mutations in these six genes account for approximately half of all cases of this condition. Mutations in the DES, MYOT, and LDB3 genes are responsible for the majority of cases of myofibrillar myopathy when the genetic cause is known.

Source: MedlinePlus Genetics

DES Gene

Ideogram of human chromosome 2

Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.

Ideogram of human chromosome 2

Selected genes, traits, and disorders associated with the chromosome listed; (blue and violet) regions reflecting the unique patterns of light and dark bands seen on human chromosomes stained to allow viewing through a light microscope; (red) the centromere, or constricted portion, of each chromosome; (yellow) chromosomal regions that vary in staining intensity and sometimes are called hererochromatin (meaning “different color”); (lines between yellow) variable regions, called stalks, that connect a very small chromosome arm (a “satellite”) to the chromosome.

Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.

DES Gene: Desmin

Normal Function

The DES gene provides instructions for making a protein called desmin. Desmin is found in heart (cardiac) muscle and muscles used for movement (skeletal muscle). Within muscle fibers, desmin proteins are important to help maintain the structure of sarcomeres, which are necessary for muscles to tense (contract). The desmin proteins surround rod-like structures called Z-discs that are located within the sarcomere. Desmin connects the Z-discs to one another, linking neighboring sarcomeres and forming myofibrils, the basic unit of muscle fibers. The connection of sarcomeres to each other to form myofibrils is essential for maintaining muscle fiber strength during repeated cycles of contraction and relaxation.

Health Conditions Related to Genetic Changes

Myofibrillar myopathy

More than 40 mutations in the DES gene have been found to cause myofibrillar myopathy. Most of these mutations change single protein building blocks (amino acids) in desmin. Mutated desmin proteins cluster together with other muscle proteins in the sarcomere to form clumps (aggregates). The aggregates prevent these proteins from functioning normally. A dysfunctional desmin protein cannot properly interact with Z-discs, leading to abnormalities of sarcomere structure and problems with the formation of myofibrils. DES gene mutations that cause myofibrillar myopathy impair the function of muscle fibers, causing weakness and the other features of this condition. People with DES gene mutations are more likely to have a weakened heart muscle (cardiomyopathy) than people with myofibrillar myopathy caused by mutations in other genes. In some cases, cardiomyopathy is the first symptom of this condition.

Arrhythmogenic right ventricular cardiomyopathy

MedlinePlus Genetics provides information about Arrhythmogenic right ventricular cardiomyopathy

Familial dilated cardiomyopathy

MedlinePlus Genetics provides information about Familial dilated cardiomyopathy

Other disorders

Mutations in the DES gene also cause a form of heart disease called dilated cardiomyopathy type 1I. This condition enlarges (dilates) and weakens the cardiac muscle, preventing it from pumping blood efficiently. DES gene mutations have also been shown to cause another form of cardiomyopathy called restrictive cardiomyopathy, in which the heart muscle is stiff and cannot fully relax after each contraction. Although cardiomyopathy is a sign of myofibrillar myopathy, these forms of cardiomyopathy are not associated with weakness of the skeletal muscles.

Mutations in the DES gene can also cause an abnormal heartbeat (arrhythmia), which may lead to heart failure and sudden death.

Researchers are not certain why some mutations in the DES gene cause these heart problems instead of myofibrillar myopathy.

Other Names for This Gene

DESM_HUMAN

Genomic Location

The DES gene is found on chromosome 2.

Source: MedlinePlus Genetics

LDB3 Gene

Ideogram of human chromosome 10

Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.

Ideogram of human chromosome 10

Selected genes, traits, and disorders associated with the chromosome listed; (blue and violet) regions reflecting the unique patterns of light and dark bands seen on human chromosomes stained to allow viewing through a light microscope; (red) the centromere, or constricted portion, of each chromosome; (yellow) chromosomal regions that vary in staining intensity and sometimes are called hererochromatin (meaning “different color”); (lines between yellow) variable regions, called stalks, that connect a very small chromosome arm (a “satellite”) to the chromosome.

Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.

LDB3 Gene: LIM Domain Binding 3

Normal Function

The LDB3 gene provides instructions for making a protein called LIM domain binding 3 (LDB3). The LDB3 protein is found in heart (cardiac) muscle and muscles used for movement (skeletal muscle). Within muscle fibers, LDB3 proteins are found in structures called sarcomeres, which are necessary for muscles to tense (contract). This protein attaches (binds) to other proteins and is involved in maintaining the stability of rod-like structures within sarcomeres called Z-discs. Z-discs link neighboring sarcomeres together to form myofibrils, the basic unit of muscle fibers. The linking of sarcomeres and formation of myofibrils provide strength for muscle fibers during repeated cycles of muscle contraction and relaxation.

Several different versions (isoforms) of the LDB3 protein are produced from the LDB3 gene.

Health Conditions Related to Genetic Changes

Myofibrillar myopathy

At least three mutations in the LDB3 gene have been found to cause myofibrillar myopathy. These mutations change single protein building blocks (amino acids) in the LDB3 protein. Mutated LDB3 proteins cluster together with other muscle proteins in the sarcomere to form clumps (aggregates). The aggregates prevent these proteins from functioning normally. A dysfunctional desmin protein cannot properly interact with Z-discs, leading to abnormalities of sarcomere structure and problems with the formation of myofibrils. LDB3 gene mutations that cause myofibrillar myopathy impair the function of muscle fibers, causing weakness and the other features of this condition.

Familial dilated cardiomyopathy

MedlinePlus Genetics provides information about Familial dilated cardiomyopathy

Left ventricular noncompaction

MedlinePlus Genetics provides information about Left ventricular noncompaction

Other disorders

Mutations in the LDB3 gene also cause a form of heart disease called dilated cardiomyopathy. This condition enlarges (dilates) and weakens the cardiac muscle, preventing it from pumping blood efficiently. Although cardiomyopathy is a sign of myofibrillar myopathy, some cases of dilated cardiomyopathy caused by LDB3 gene mutations are not associated with weakness of the skeletal muscles. Researchers have identified at least two mutations in the LDB3 gene that cause dilated cardiomyopathy without the other features of myofibrillar myopathy. These mutations, written as Asp117Asn and Lys136Met, change single amino acids in the LDB3 protein. Researchers are not certain why some mutations in the LDB3 gene cause dilated cardiomyopathy instead of myofibrillar myopathy.

Other Names for This Gene

LDB3_HUMAN
LDB3Z1
LDB3Z4
LIM domain-binding protein 3
ZASP

Genomic Location

The LDB3 gene is found on chromosome 10.

Source: MedlinePlus Genetics

MYOT Gene

Ideogram of human chromosome 5

Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.

Ideogram of human chromosome 5

Selected genes, traits, and disorders associated with the chromosome listed; (green and violet) regions reflecting the unique patterns of light and dark bands seen on human chromosomes stained to allow viewing through a light microscope; (red) the centromere, or constricted portion, of each chromosome; (yellow) chromosomal regions that vary in staining intensity and sometimes are called hererochromatin (meaning “different color”); (lines between yellow) variable regions, called stalks, that connect a very small chromosome arm (a “satellite”) to the chromosome.

Image by Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science, the Biological and Environmental Research Information System, Oak Ridge National Laboratory.

MYOT Gene: Myotilin

Normal Function

The MYOT gene provides instructions for making a protein called myotilin. Myotilin is found in heart (cardiac) muscle and muscles used for movement (skeletal muscle). Within muscle fibers, myotilin proteins are found in structures called sarcomeres, which are necessary for muscles to tense (contract). Myotilin attaches (binds) to other proteins to help form sarcomeres. Myotilin is also involved in linking neighboring sarcomeres to each another to form myofibrils, the basic unit of muscle fibers. The connection of sarcomeres to each other and the formation of myofibrils are essential for maintaining muscle fiber strength during repeated cycles of contraction and relaxation.

Health Conditions Related to Genetic Changes

Myofibrillar myopathy

At least five mutations in the MYOT gene have been found to cause myofibrillar myopathy. Most of these mutations are located in an area of the gene known as exon 2. MYOT gene mutations that cause myofibrillar myopathy change single protein building blocks (amino acids) in myotilin. Mutated myotilin proteins cluster together with other muscle proteins in the sarcomere to form clumps (aggregates). The aggregates prevent these proteins from functioning normally. A dysfunctional myotilin protein cannot properly bind with other proteins, preventing the formation of sarcomeres and myofibrils. MYOT gene mutations that cause myofibrillar myopathy impair the function of muscle fibers, causing weakness and the other features of this condition.

Limb-girdle muscular dystrophy

MedlinePlus Genetics provides information about Limb-girdle muscular dystrophy

Other Names for This Gene

MYOTI_HUMAN
TTID

Genomic Location

The MYOT gene is found on chromosome 5.

Source: MedlinePlus Genetics

Inheritance

Genetics and Inheritance

Image by TheVisualMD

Genetics and Inheritance

Infant and his chromosomes

Image by TheVisualMD

How Is Myofibrillar Myopathy Inherited?

In some cases, people with an autosomal dominant form of MFM are the first people in their family who are diagnosed with the disease. This may occur for two reasons. First, it may be that the person diagnosed with the disease is the only person in the family with a genetic change. This means that the genetic change is new (de novo) in the affected individual and it was not inherited from either parent. In other cases, it may be that the parents of the affected individual also have MFM, but they have a form of the disease that is slowly progressing or has not yet been diagnosed. Therefore, if a person is diagnosed with MFM and the exact genetic cause is known, it is important that their parents also receive genetic testing to determine if one of them also has the disease.

MFM can exhibit reduced penetrance and variable expressivity. Reduced penetrance means that some people who have genetic changes that cause MFM may not have signs or symptoms of the disease. However, these people can still pass on MFM to their children. Variable expressivity means that the exact symptoms of each person with MFM can differ, even within the same family. For example, some affected individuals may have both cardiomyopathy and muscle weakness, while others may just have one or the other.

If MFM is caused by a change in the FHL1 gene, it is inherited in an X-linked manner. This means that the FHL1 gene is located on the X chromosome. The X chromosome is one of the sex chromosomes. Each woman has two X chromosomes, and each man has one X chromosome and one Y chromosome. Because men have only one X chromosome, they only have one copy of the FHL1 gene. If this gene has a mutation, they will have MFM. However, women who have changes in one copy of the FHL1 gene are known as carriers of the disease. Most carriers do not have signs or symptoms of MFM because they have another working copy of FHL1.

If MFM is caused by a change in CRYAB, it is inherited in an autosomal recessive manner. This means that both copies of the CRYAB gene must be changed in order to have symptoms of the disease. Men and women with a mutation in only one copy of the CRYAB gene are known as carriers, meaning they do not have signs or symptoms of the disease. When two carriers of a CRYAB mutation have children together, for each child there is a:

25% chance that the child will have MFM
50% chance that the child will be a carrier of MFM like the parents
25% chance that the child will have two working copies of CRYAB, so the child will not have MFM and will not be a carrier.

Source: Genetic and Rare Diseases (GARD) Information Center

Symptoms

Three distinct types of muscles (L to R): Smooth (non-striated) muscles in internal organs, cardiac or heart muscles, and skeletal muscles

Image by Scientific Animations, Inc.

Three distinct types of muscles (L to R): Smooth (non-striated) muscles in internal organs, cardiac or heart muscles, and skeletal muscles

Three distinct types of muscles (L to R): Smooth (non-striated) muscles, cardiac or heart muscles, and skeletal muscles.

Image by Scientific Animations, Inc.

What Are the Signs and Symptoms of Myofibrillar Myopathy?

Muscle weakness most often begins in the hands and feet (distal muscles), but some people first experience weakness in the muscles near the center of the body (proximal muscles). Facial muscle weakness can rarely cause swallowing and speech difficulties. The muscle weakness is progressive, meaning that it tends to worsen over time.

Other signs and symptoms of MFM can include an enlarged and weakened heart muscle (cardiomyopathy) or an abnormal heart rhythm (arrhythmia), muscle pain (myalgia), and loss of sensation and weakness in the limbs (peripheral neuropathy). For some people, as the disease progresses, the muscles of the lungs may also be affected, which can result in respiratory failure. Individuals with this disease may have skeletal problems including joint stiffness (contractures) and abnormal curvature of the spine (scoliosis). Rarely, people with this disease develop clouding of the front surface of the eyes (cataracts).

Source: Genetic and Rare Diseases (GARD) Information Center

Diagnosis

Electromyographic recording at adductor pollicis muscle and stimulation of the ulnar nerve

Image by Paul Anthony Stewart/Wikimedia

Electromyographic recording at adductor pollicis muscle and stimulation of the ulnar nerve

Electromyography is a form of quantitative neuromuscular function monitoring. Electromyography can be used to monitor the effects of and recovery from muscle relaxants when used as part of general anaesthesia.

Image by Paul Anthony Stewart/Wikimedia

How Is Myofibrillar Myopathy Diagnosed?

Electromyography: a study measuring the response of muscles to an electrical stimulus
Muscle biopsy: a sample of the muscle is taken to determine how it looks under a microscope
Creatine kinase test: a test of an enzyme that can provide information about the health of the muscles

If myofibrillar myopathy is suspected, genetic testing of the genes associated with the disease can be used to confirm the diagnosis and provide more information about long-term outlook.

Source: Genetic and Rare Diseases (GARD) Information Center

Electromyography (EMG) and Nerve Conduction Studies

Electromyography (EMG) and Nerve Conduction Studies

Also called: Electrodiagnostic study, Electrodiagnosis, EDX

Electromyography (EMG) and nerve conduction studies are tests that measure the electrical activity of muscles and nerves. They are used to find out if you have a disorder of your muscles, nerves, or both.

Electromyography (EMG) and Nerve Conduction Studies

Also called: Electrodiagnostic study, Electrodiagnosis, EDX

Electromyography (EMG) and nerve conduction studies are tests that measure the electrical activity of muscles and nerves. They are used to find out if you have a disorder of your muscles, nerves, or both.

Electromyography (EMG) and nerve conduction studies are tests that measure the electrical activity of muscles and nerves. Nerves send out electrical signals to make your muscles react in certain ways. As your muscles react, they give off these signals, which can then be measured.
- An EMG test looks at the electrical signals your muscles make when they are at rest and when they are being used.
- A nerve conduction study measures how fast and how well the body's electrical signals travel down your nerves.
EMG tests and nerve conduction studies can both help find out if you have a disorder of your muscles, nerves, or both. These tests can be done separately, but they are usually done at the same time.
You may need these tests if you have symptoms of a muscle or nerve disorder. These symptoms include:
- Muscle weakness
- Tingling or numbness in arms, legs, hands, feet, and/or face
- Muscle cramps, spasms, and/or twitching
- Paralysis of any muscles
For an EMG test:
- You will sit or lie down on a table or bed.
- Your provider will clean the skin over the muscle being tested.
- Your provider will place a needle electrode into the muscle. You may have slight pain or discomfort when the electrode is inserted.
- The machine will record the muscle activity while your muscle is at rest.
- Then you will be asked to tighten (contract) the muscle slowly and steadily.
- The electrode may be moved to record activity in different muscles.
- The electrical activity is recorded and shown on a video screen. The activity is displayed as wavy and spiky lines. The activity may also be recorded and sent to an audio speaker. You may hear popping sounds when you contract your muscle.
For a nerve conduction study:
- You will sit or lie down on a table or bed.
- Your provider will attach one or more electrodes to a certain nerve or nerves using tape or a paste. The electrodes, called stimulating electrodes, deliver a mild electrical pulse.
- Your provider will attach different types of electrodes to the muscle or muscles controlled by those nerves. These electrodes will record the responses to the electrical stimulation from the nerve.
- Your provider will send a small pulse of electricity through the stimulating electrodes to stimulate the nerve to send a signal to the muscle.
- This may cause a mild tingling feeling.
- Your provider will record the time it takes for your muscle to respond to the nerve signal.
- The speed of the response is called the conduction velocity.
If you are having both tests, the nerve conduction study will be done first.
If your results were not normal, it can indicate a variety of different conditions. Depending on which muscles or nerves are affected, it may mean one of the following:
- Carpal tunnel syndrome, a condition that affects nerves in the hand and arm. It's usually not serious, but can be painful.
- Herniated disc, a condition that happens when a part of your spine, called a disc, is damaged. This puts pressure on the spine, causing pain and numbness
- Guillain-Barré syndrome, an autoimmune disorder that affects the nerves. It can lead to numbness, tingling, and paralysis. Most people recover from the disorder after treatment
- Myasthenia gravis, a rare disorder that causes muscle fatigue and weakness.
- Muscular dystrophy, an inherited disease that seriously affects muscle structure and function.
- Charcot-Marie-Tooth disease, an inherited disorder that causes nerve damage, mostly in the arms and legs.
- Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease. This is a progressive, ultimately fatal, disorder that attacks nerve cells in your brain and spinal cord. It affects all the muscles you use to move, speak, eat, and breathe.
If you have questions about your results, talk to your health care provider.

Additional Materials (7)

Schematic diagram of normal sinus rhythm for a human heart as seen on ECG.

Schematic representation of normal ECG trace (sinus rhythm) with waves, segments, and intervals labeled. The QT interval is marked by blue stripe at bottom.

Image by Created by Agateller (Anthony Atkielski), converted to svg by atom.

Limb leads

Limb leads, standard placement of the limb leads for electrocardiography.

Image by !Original: MoodyGrooveVector: Twisp This SVG diagram includes elements that have been taken or adapted from this diagram: Wikicouple.svg. /Wikimedia

Precordial leads in ECG

Placement of the precordial leads in electrocardiography.

Image by Mikael Häggström/Wikimedia

Limb leads of EKG

Derivation of the limb leads

Image by Npatchett/Wikimedia

Spatial orientation of EKG leads

Spatial orientation of EKG leads

Image by Npatchett

Animation of ECG Limb Leads and Electrical Conduction Through the Heart

This is a 30-frame animation of how the electrical conduction through the heart creates a normal ECG for all 3 limb leads.

Image by 10ebyu10e/Wikimedia

Willem Einthoven ECG

In contrast to what the name of this file may suggest, this picture does not represent the ECG machine built by Willem Einthoven and his team. It shows an early commercial ECG machine, built in 1911 by the Cambridge Scientific Instrument Company (Christoph Zywietz, A Brief History of Electrocardiography - Progress through Technology; S. L. Barron, The development of the electrocardiograph in Great Britain, British Medical Journal 1:720, 25 March 1950) to measure the human electrocardiogram according to the standards developed by Einthoven.

Image by /Wikimedia

Schematic diagram of normal sinus rhythm for a human heart as seen on ECG.

Created by Agateller (Anthony Atkielski), converted to svg by atom.

Limb leads

!Original: MoodyGrooveVector: Twisp This SVG diagram includes elements that have been taken or adapted from this diagram: Wikicouple.svg. /Wikimedia

Precordial leads in ECG

Mikael Häggström/Wikimedia

Limb leads of EKG

Npatchett/Wikimedia

Spatial orientation of EKG leads

Npatchett

Animation of ECG Limb Leads and Electrical Conduction Through the Heart

10ebyu10e/Wikimedia

Willem Einthoven ECG

/Wikimedia

Creatine Kinase (CK) Blood Test

Creatine Kinase (CK) Blood Test

Also called: Creatine Kinase, Total CK, Creatine Phosphokinase, CPK

This test measures the amount of creatine kinase (CK) in a sample of your blood. CK is an enzyme that helps in producing energy from muscles. High CK levels may be a sign of damage or disease in your muscles, heart, or brain.

Creatine Kinase (CK) Blood Test

Also called: Creatine Kinase, Total CK, Creatine Phosphokinase, CPK

This test measures the amount of creatine kinase (CK) in a sample of your blood. CK is an enzyme that helps in producing energy from muscles. High CK levels may be a sign of damage or disease in your muscles, heart, or brain.

{"label":"Creatine kinase reference range","scale":"lin","step":0.1,"hideunits":false,"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":24},"text":"Low CK levels often result from an individual having low muscle mass or body weight. People who have been confined to bed rest for extended periods of time will display abnormally low CK levels. A low CK level could be the result of alcoholic liver disease or a connective tissue disease.","conditions":["Alcoholic liver disease","Cachexia","Connective tissue disease","Kidney disease","Extreme weight loss","Lupus","Malnutrition","Myasthenia gravis","Muscular dystrophy","Rheumatoid arthritis","Sj\u00f6gren syndrome"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":24,"max":204},"text":"CK levels are a reflection of total muscle mass. The normal range for total CK varies by age and gender. Race is also known to affect CK levels. Black people have naturally higher levels of CK. Some people with a muscular build also have higher levels of CK. Women generally have lower CK levels than men, because they typically have less muscle mass. Additionally, a pregnant woman will display lower CK levels than a non-pregnant woman.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":204,"max":500},"text":"A high CK result generally means you have some type of muscle damage. High CK is found after trauma, surgery, and exercise. You may have more than one CK test to see if your levels go up or down. CK levels that stay high or increase may mean that muscle damage is continuing to happen. Further testing may be necessary to determine the type of muscles affected.","conditions":["Brain injury","Stroke","Heart attack","Seizures","Muscle disorder","Myopathy","Dermatomyositis","Polymyositis","Rhabdomyolysis","Electric shock","Myocarditis","Pulmonary infarction","Malignant hyperthermia","Hypothyroidism","Hyperthyroidism"]}],"units":[{"printSymbol":"U\/L","code":"U\/L","name":"enzyme unit per liter"}],"value":114,"disclaimer":"Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are \"within normal limits.\""}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
U/L
24
204
Your result is Normal.
CK levels are a reflection of total muscle mass. The normal range for total CK varies by age and gender. Race is also known to affect CK levels. Black people have naturally higher levels of CK. Some people with a muscular build also have higher levels of CK. Women generally have lower CK levels than men, because they typically have less muscle mass. Additionally, a pregnant woman will display lower CK levels than a non-pregnant woman.
Related conditions
A CK test is most often used to help diagnose and monitor:
- Muscle injuries, including injuries from accidents, serious burns, or extreme exercise.
- Muscle diseases, including:
  Muscular dystrophy, a group of inherited muscle diseases that weaken muscles over time.
  Rhabdomyolysis, or "rhabdo," a rapid breakdown of muscle tissue which releases proteins and electrolytes into the blood. This uncommon condition can damage the heart and lead to sudden kidney failure. Rhabdo has many causes, including serious injuries, working in very hot places, overusing muscles, and certain medicines and medical conditions that affect the muscles.
  Myositis, a group of rare diseases that involve long-term muscle inflammation (swelling), weakness, and sometimes pain.
In certain cases, a CK test may be used to help diagnose a heart attack. Another blood test, called a troponin test is used more often. That's because troponin testing is better at finding damage to the heart muscle from a heart attack.
If you've had a stroke, a CK test may be done to find out how severe it was. The test may also help predict the chance that you may have another stroke.
You may need a CK test if you have symptoms of a muscular disorder. These include:
- Muscle pain and/or cramps
- Muscle weakness
- Balance problems and/or falling a lot
- Numbness or tingling
- Dark colored urine (pee)
- Swollen legs or feet
You may also need this test if you:
- Have had an injury that crushed or tore your muscles
- Have had serious burns
- Take certain medicines that may cause muscle damage, such as statins to lower blood cholesterol
- Have had a stroke or traumatic brain injury (TBI)
Normal CK levels for you will depend on:
- Your age, sex, and race
- How much muscle you have
- How physically active you are
If your CK level is higher than normal, it usually means you have some type of muscle damage. CK levels may not reach their highest until up to two days after certain injuries. So, you may have more than one CK test to see if your levels go up or down. CK levels that stay high or increase may mean that muscle damage is continuing to happen.
But a CK test result can't show where the damage is or what's causing it. Your provider will consider your symptoms and medical history to understand what your test results mean.
If the source of high or increasing CK levels isn't clear, you may need a more specific type of CK test to find out if the CK is coming from your muscles, heart, or brain. This more specific test is called a CK isoenzymes test.
To diagnose the condition causing high CK levels, you may need other types of tests, too. The tests you have will depend on which types of CK enzymes are high as well as your symptoms and medical history.
If you have questions about any of your test results or diagnosis, talk with your provider.
1. Creatine Kinase: MedlinePlus Medical Test [accessed on Jan 27, 2024]
2. Creatine phosphokinase test: MedlinePlus Medical Encyclopedia [accessed on Jan 27, 2024]
3. Creatine Kinase (Blood) - Health Encyclopedia - University of Rochester Medical Center [accessed on Jan 27, 2024]
4. HealthMatters.io LLC. Creatine kinase - Lab Results explained | HealthMatters.io [accessed on Jan 27, 2024]
5. Creatine kinase (CK) Test - Bay Biosciences, LLC.. Oct 19, 2022 [accessed on Jan 27, 2024]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (16)

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Blockage Leads to Heart Attack

Risk factors increase the likelihood that you'll develop cardiovascular disease, and the more risk factors you have, the greater your chances of developing it. Fortunately, most of these risk factors are within your control, like high cholesterol and high blood pressure levels, being overweight, smoking, lack of exercise, overconsumption of alcohol, unmanaged diabetes, and stress. Factors you can't control include genetics and aging.

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Women's Cardiovascular Health

Watch Dr. Mehmet Oz and other renowned cardiologists as they talk about this major killer, known in the medical world as a "myocardial infarction." Step inside the human body in a way that lets you completely understand what a heart attack is all bout, how and why they happen, what to do in the event of a heart attack, and how you can take steps to avoiding one.

Video by TheVisualMD

Heart attack (myocardial infarction) warning signs in women.

Image by U.S. Department of Health and Human Services Office on Women's Health

Myocardial Infarction (Heart Attack)

An illustration depicting a heart attack and chest pain.

Image by BruceBlaus

Myocardial infarction

Inferior wall infarction, short axis echocardiography view

Image by Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist

Myocardial infarction - Post-infarction ventricular septal defect

Post-infarction ventricular septal defect, short axis echocardiography view

Image by Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist

Myocardial infarction - Post-infarction ventricular septal defect

Post-infarction echocardiographic views of ventricular septal defect

Image by Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist

Heart Attack Symptoms

Symptoms of a heart attack are often more severe and longer-lasting than those of angina. Heart attacks can occur at any time or place, when you're resting or when you're in motion. Heart attacks can strike without warning, but there may be signs and symptoms, like angina, in advance.

Image by TheVisualMD

Heart Attack Symptoms

Symptoms of a heart attack are often more severe and longer-lasting than those of angina. Heart attacks can occur at any time or place, when you're resting or when you're in motion. Heart attacks can strike without warning, but there may be signs and symptoms, like angina, in advance.

Image by TheVisualMD

What Is a Heart Attack?

Sometimes the surface of a plaque in a coronary artery ruptures. The rupture releases substances that make platelets stickier, encouraging clots to form on the surface of the plaque. The clot can block the flow of blood through the already-narrowed artery entirely. Without blood, heart muscle tissue starts to die in what's termed a myocardial infarction- a heart attack.

Image by TheVisualMD

Lipoprotein (a) or Lp(a), Heart Attack

LDL, HDL and total cholesterol have become standard biomarkers for heart disease. And yet half of all people who suffer heart attacks have normal cholesterol levels. For that reason, researchers have looked for other biomarkers that might help identify people at risk for cardiovascular disease. Lp(a) is a lipoprotein that closely resembles LDL, and like LDL, elevated levels of Lp(a) are associated with a higher risk of heart disease. Unlike LDL, however, Lp(a) levels are believed to be largely genetic.

Image by TheVisualMD

Cholesterol, Low-Density Lipoprotein (LDL), Heart Disease, Heart Attack

There are two main types of cholesterol particles found in the bloodstream: HDL (high-density lipoprotein, or \"good\" cholesterol); and LDL (low-density lipoprotein, or \"bad\" cholesterol). LDL often leads to the formation of plaque deposits that can clog arteries and increase the risk of heart disease. Each year 1.2 million people have a heart attack (for nearly half of them, it's not their first). More than 600,000 individuals die from heart disease each year, making it the leading cause of death for both men and women.

Image by TheVisualMD

Heart Attack Caused by Ischemia

Thromboembolisms can cause heart attacks. A clot may lodge in one of the heart's coronary arteries (the arteries that supply the heart muscle tissue with blood) and block blood flow. The tissue becomes starved of oxygen (a condition called ischemia) and is damaged or dies.

Image by TheVisualMD

Lipoprotein (a) or Lp(a), Cardiovascular Disease

In order for fats to travel freely in the bloodstream, they must be packaged as lipoproteins. The two main types are HDL (high-density lipoprotein, or \"good\" cholesterol) and LDL (low-density lipoprotein, or \"bad\" cholesterol). There are other lipoproteins, however. Lipoprotein (a), or Lp(a), is one that resembles LDL and, like LDL, elevated levels of Lp(a) are associated with a higher risk of cardiovascular disease. Unlike LDL, however, Lp(a) levels are believed to be largely genetic.

Image by TheVisualMD

Heart attack (myocardial infarct) diagnosis | NCLEX-RN | Khan Academy

Video by khanacademymedicine/YouTube

What causes a heart attack?

Video by multiedmedical/YouTube

0:23

Blockage Leads to Heart Attack

TheVisualMD

2:56

Women's Cardiovascular Health

TheVisualMD

Heart attack (myocardial infarction) warning signs in women.

U.S. Department of Health and Human Services Office on Women's Health

Myocardial Infarction (Heart Attack)

BruceBlaus

Myocardial infarction

Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist

Myocardial infarction - Post-infarction ventricular septal defect

Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist

Myocardial infarction - Post-infarction ventricular septal defect

Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist

Heart Attack Symptoms

TheVisualMD

Heart Attack Symptoms

TheVisualMD

What Is a Heart Attack?

TheVisualMD

Lipoprotein (a) or Lp(a), Heart Attack

TheVisualMD

Cholesterol, Low-Density Lipoprotein (LDL), Heart Disease, Heart Attack

TheVisualMD

Heart Attack Caused by Ischemia

TheVisualMD

Lipoprotein (a) or Lp(a), Cardiovascular Disease

TheVisualMD

10:45

Heart attack (myocardial infarct) diagnosis | NCLEX-RN | Khan Academy

khanacademymedicine/YouTube

2:54

What causes a heart attack?

multiedmedical/YouTube

Treatment

physical therapy

Image by Cabblow

physical therapy

physical rehabilitation

Image by Cabblow

How Might Myofibrillar Myopathy Be Treated?

For some affected individuals, the progressive muscle weakness may affect the ability of the muscles of the lungs to work properly, especially at night. This may require respiratory support such as a ventilator to make sure affected individuals are breathing properly.

Source: Genetic and Rare Diseases (GARD) Information Center

Prognosis

Treatment and Prognosis varies depending on the type of condition and the age of symptom onset.

Image by 4144132

Treatment and Prognosis varies depending on the type of condition and the age of symptom onset.

Prognosis varies depending on the type of MND and the age of symptom onset.

Image by 4144132

What Is the Long-Term Outlook for People with Myofibrillar Myopathy?

Because MFM shows variable expressivity, the exact signs and symptoms for each person cannot be predicted, including whether or not an affected individual will have heart problems or breathing problems. If the heart problems and breathing problems are managed, people with MFM are expected to have a normal life expectancy.

Source: Genetic and Rare Diseases (GARD) Information Center

Additional Materials (1)

Prognosis Icon

Image by mcmurryjulie/Pixabay

Prognosis Icon

mcmurryjulie/Pixabay

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Myofibrillar Myopathy

Myofibrilar myopathy (MFM) is a neuromuscular disease characterized by slowly progressive muscle weakness that can involve both proximal muscles (such as hips and shoulders) and distal muscles (those further away from the trunk). Explore symptoms, causes, and genetics of this rare condition.

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