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Glossary of medical terms

You may come across some of the following terms being used in relation to your GSD.

We have tried to provide a layman’s explanation of each term. Where there is a difference in meaning or application between the various GSDs, we have highlighted this.

For more technical medical definitions try this medical dictionary.
Go to online medical dictionary.

Please note: on some devices, you may need to click a second time on your chosen letter of the alphabet.

Category: All Categories Liver Muscle Pompe
  • Another name for Pompe disease. Acid Maltase is a term for the GAA enzyme. People with Pompe disease lack or produce very low levels of this enzyme, they have a deficiency. This term was more common historically and in the USA.
  • Sudden and severe.
  • ARF, a sudden decline in kidney function. Requires urgent medical attention. Muscle GSDs: ARF can be caused by the breakdown of muscle from anaerobic activity.
  • ATP, a molecule in muscle cells which serves as an energy source for the metabolic process.
  • Exercise which requires oxygen to assist in converting fuel sources into energy. Walking is a good example of aerobic exercise. This is good exercise for those with McArdle disease.
  • ALT, an enzyme produced mainly in the liver. Also known as alanine transaminase.
  • A protein made by the liver. Controls fluid in the blood and tissues.
  • ALP/ALK-PHOS, an enzyme produced in the bile ducts and elsewhere in the body.
  • Alanine transaminase (also know as alanine aminotransferase) an enzyme found mostly in the liver. Levels are sometimes higher in people with Pompe disease.
  • A lack of iron can lead to a person having fewer red blood cells than usual. There can also be other causes.
  • Without oxygen. A type of activity which uses stored energy rather than blood-borne energy.
  • Exercise which does not need oxygen to utilise fuel sources. Weightlifting is a good example of anaerobic exercise. This type of exercise requires the conversion of glycogen to glucose.
  • A connection made surgically between two tubes.
  • A scan using x-rays to see blood vessels. It can be used to see the blood vessels which supply the liver.
  • Irregular rhythm often describing the way the heart beats. This includes; too fast, too slow or fluttering.
  • Fluid collecting in the abdomen.
  • An enzyme produced mainly in the liver.
  • Collapse or closure of a lung.
  • Blocked, destroyed or missing.
  • Wasting away or degeneration.
  • One pattern in which a child inherits genes from parents. The disease only occurs when a child inherits two copies of a defective gene (one from each parent).
  • Treatment for varices. Surgical elastic bands are placed around the varices during an endoscopy.
  • Green/yellow liquid containing bile salts, bilirubin and cholesterol.
  • Acids found in bile which can be converted into bile salts.
  • The system of tubes which carry bile from the liver and gall bladder and drain into the intestine.
  • Product of the breakdown of old red blood cells. It has a yellow colour which gives stool and blood their colour. Bilirubin travels in the blood stream to the liver where it has a sugar added and becomes conjugated bilirubin.
  • Procedure to take a small sample of tissue to test in the laboratory. In GSDs these are usually from the liver or muscle.
  • Type of non-invasive ventilator that helps with breathing. This type is Bi-Level Positive Airway Pressure which delivers variable respiratory and lower expiratory pressure for easier breathing.
  • Amount of glucose that is in your blood.
  • BMI, a test using height and weight to measure whether an individual is a healthy weight.
  • A short, soft, narrow plastic tube temporarily put into a vein so medicines/fluids/blood etc. can be given intravenously (IV) as needed.
  • A type of compound, such as starches and sugars, found in food. Broken down in the body to form energy.
  • Of the heart.
  • Abnormal enlargement of the heart.
  • Disease of the heart muscle, where the walls of the heart chambers have become stretched, thickened or stiff. This affects the heart's ability to pump blood around the body.
  • The heart and blood vessels which transport nutrients and oxygen around the body.
  • Basic structural and functional component of all living things.
  • CVL, a central line is similar to a cannula but is a longer tube used to give medicine, fluid, nutrition or blood directly into a larger vein. Can also be used to take blood samples. Long, narrow plastic tube placed into a vein in the neck, chest or groin, used for longer than a cannula.(...)
  • Inflammation or infection of bile ducts which can cause poor bile flow from the liver and liver damage.
  • Reduction or blockage of bile flow.
  • An illness or condition which lasts over a period of time.
  • Inflammation of the liver that lasts over a period of time. Liver cells may be destroyed by the inflammation.
  • Any condition where the blood cannot clot properly.
  • CT Scan, x-rays are used to create a detailed picture of parts of the body.
  • Condition which is present from birth.
  • A type of non-invasive ventilator that helps with breathing. This type is Continuous Positive Airway Pressure which applies mild air pressure on a continuous basis to keep the airways continuously open.
  • Abbreviated to CK or CPK. An enzyme which is used in the formation of ATP in muscle. People muscle GSD have a raised level of CK in their blood and this is often an early sign that something is wrong.
  • Cross Reacting Immune Material. If the body is producing a low level of GAA enzyme when the enzyme treatment [ERT] is given as a treatment the body recognizes it. However, if the body has zero GAA [CRIM Negative] when the enzyme treatment is given the body treats it as a foreign object and the(...)
  • Relating to the gall bladder
  • CMV, a virus belonging to the herpes virus group.
  • A degree-qualified health professional who helps to promote nutritional well-being, treat disease and prevent nutrition related problems. They provide practical, safe advice, based on current scientific evidence.
  • Expansion or enlargement.
  • Tube which fluid can pass through from one part of the body to another, e.g. bile ducts.
  • The Department for Work and Pensions is responsible for welfare, pensions and child maintenance policy. As the UK's biggest public service department it administers the State Pension and a range of working age, disability and ill health benefits.
  • Abnormal development of body tissue or an organ
  • Electrocardiogram. A recording of the beating of the heart made by placing sensors on your chest and limbs. It is printed out as a trace or graph.
  • Echo, a scan of the heart using high frequency sound waves, similar to an ultrasound of the abdomen.
  • The measurement of electrical activity in the heart and its recording as a visual trace, using electrodes placed on the skin of the limbs and chest.
  • Changes in the brain which can be due to liver failure. The build-up of toxins in the blood can lead to tiredness, irritability and personality changes.
  • Using a flexible, thin tube with a camera attached to look at the inside of the upper end of the digestive system. It is passed through the mouth and down the oesophagus (the food tube).
  • Feeding through a tube directly into the stomach or part of the intestine.
  • A protein which the body uses to make a chemical reaction happen.
  • EBV, a virus which causes glandular fever.
  • Endoscopic retrograde cholangiopancreatography, a special x-ray used to examine bile ducts under general anaesthetic.
  • Enzyme Replacement Therapy.
  • Employment and Support Allowance is for people of working age who cannot work because of illness or disability. Entitlement usually depends upon your National Insurance record (except for some young adults), and may be subject to a medical assessment.
  • Also known as stool or poo.
  • Scar tissue which replaces normal tissue which, when extensive, is known as cirrhosis.
  • Another name for GSD3 in honour of American clinician Gilbert Burnett Forbes.
  • FBC, blood test measuring all of the different types of cells in the blood.
  • Severe, sudden form of liver failure. More commonly known as acute liver failure.
  • Lysosomal acid alpha-glucosidase. One of the enzymes needed in the metabolism of glycogen but missing or in very low levels in people with Pompe disease.
  • Small sac which stores and releases bile made by the liver.
  • Stones which can be formed by bile and collect in the gall bladder and bile ducts. They can cause pain and may pass into the common bile duct and cause cholangitis or obstructive jaundice.
  • Study of the digestive system.
  • An individual is put into a state of controlled unconsciousness.
  • Made up of DNA and provide instructions for the body.
  • All the genes together are called the genome. Each living thing has its own genome, the entire collection of genes.
  • The end product of carbohydrate metabolism and also found in certain foods such as fruit. The chief source of energy.
  • The form in which glucose is stored in the muscles and in the liver. It has to be converted back to glucose to be used for energy.
  • The conversion of glycogen and glucose, via a series of steps, finally into ATP which energises the muscle. The process does not use oxygen and is thus anaerobic.
  • Organ, tissue or cells used for transplantation.
  • Vomiting blood.
  • Part of a red blood cell which carries oxygen around the body.
  • Of the liver.
  • Blood vessel which brings blood with oxygen to the liver.
  • Blood vessel which takes blood away from the liver.
  • Inflammation of the liver.
  • Study of the liver.
  • Enlargement of the liver.
  • Using water as a treatment or therapy. This can be either cold, warm or hot water and often means exercises or movements in the water.
  • High blood pressure.
  • Deficiency of glucose in the bloodstream. Often called low blood sugar. May be associated with symptoms such as anxiety, sweating, tremor, palpitations, nausea, and pallor.
  • Low blood pressure.
  • Poor or low muscle tone, often seen as floppy, weak muscles.
  • Something with no known cause.
  • Protection against a particular disease, occurring naturally or due to vaccination.
  • Protein which plays a role in the immune system.
  • Medications which make the immune system less active.
  • Number of new cases of a disease over a certain period of time in a population.
  • INR, a measure of how well blood clots.
  • Into the vein. Some fluids and drugs are delivered into the veins.
  • Muscular action in which tension is developed without contraction of the muscle. Also known as 'static' exercise as there is no movement of the muscle. For example: clenching fists, holding something up or pushing.
  • High level of bilirubin in the blood leading to yellowing of the skin and/or the whites of the eyes.
  • Operation to get bile flowing from the liver to the intestine in biliary atresia. Bile ducts are removed and a piece of intestine is used to replace the ducts.
  • An acid which is made as a biproduct of the muscle using carbohydrate. Normally there is a rise of lactic acid in the bloodstream on exercise.McArdle disease - it does not rise. The lack of this rise can be a help in diagnosis.
  • LFT, blood tests which can show how well the liver is working.
  • Clear, watery liquid derived from body tissues which carries white blood cells and fats. It travels through the lymphatic system of the body.
  • Operation to remove the lymph nodes.
  • Found inside a cell, they digest or recycle waste from cell metabolism.
  • A severe form of fever caused by a reaction to certain anaesthetics and muscle relaxants. Those with muscle GSD disease may be at an increased risk of malignant hyperthermia and should always tell their anaesthetist about their condition before having a general anaesthetic.
  • A condition in which metabolism is affected.
  • Processes in the body which break down and build up different chemicals in the use of energy. The process simply starts with taking in food.
  • A very small organ within the cells of the muscle which is responsible for energy production from fuels. Through regular aerobic exercise the number of mitochondria can be increased, which boosts the aerobic capacity of the muscle.
  • A medical procedure in which a small piece of muscle is removed from the body and tested.
  • A permanent change or alteration. Can occur within the gene.
  • Pain in a muscle or muscles. This the main symptom of muscle GSDs.
  • A protein found in red skeletal muscle.
  • Presence of myoglobin in the urine. Muscle damage releases myoglobin into the blood and the kidneys remove it from the blood to the urine. An excessive amount of myoglobin in the blood can "block" the kidneys and cause acute renal failure.
  • A disease of the muscle.
  • The muscle type of phosphorylase. Deficient in McArdle disease. There are also brain and neo-natal forms.
  • NG feeding, giving food through a tube which goes through the nose and down the throat to the stomach.
  • Tube used during nasogastric feeding.
  • NJ, small tube that is passed up the nose and down the throat, through the stomach, and into the small intestine used for feeding.
  • The course of the disease and how it progresses when no treatment is given. Treatments can change the course of the disease and alter the way it progresses from the natural history.
  • Of the muscle and nerves. People with muscle glycogen storage disease may be diagnosed and/or cared for by a neuromuscular consultant.
  • Non Invasive Ventilation when air is supplied via a mask over the nose and/or mouth.
  • Provides practical support to help children and adults of all ages, with mental, physical, social or learning disabilities, to independently carry out everyday tasks or occupations with more confidence and independence.
  • A build up of fluid in the affected tissues. Also known as fluid retention.
  • Bones that are weaker than normal.
  • PN, feeding nutrients directly into the vein when an individual cannot eat normally.
  • PTC, special x-ray which looks at the bile ducts. Done under a general anaesthetic using a needle which is inserted through the skin of the abdomen into the bile ducts.
  • Person who takes blood samples.
  • An enzyme used in the conversion of stored glycogen to glucose so that it can be utilised for energy.
  • A therapy to help restore movement and function when someone is effected by injury, illness or disability. A neuromuscular physiotherapist would be needed to teat a person with a glycogen storage disease affecting muscle.
  • Part of the blood, important for clotting the blood. Can be low in people with liver disease.
  • PCR, test which checks for a virus in the blood.
  • A medical appliance inserted under the skin to allow easy access for inserting a needle.
  • High blood pressure in the portal vein, may occur due to scarring of the liver or a blockage of the portal vein.
  • Main vein carrying blood from the intestine to the liver.
  • Complex organic compunds found in the body and in foods such as meat and eggs. Consist mainly of amino acids. They serve a number of functions including as enzymes and are involved in oxygen transport and muscle contraction. As a fuel, proteins contain 4 calories (kcal) per gram, just like(...)
  • The opposite of distal. These are the muscles closest to the midline; the central part of the body. Pompe: often there is weakness of the limb girdle, this too is a part of the central core of the body.
  • Itching of the skin.
  • Of the lungs.
  • Of the kidneys.
  • Related to breathing.
  • The destruction of cells in the skeletal muscles. In McArdle disease this arises from fixed spasm of the muscle caused by excessive activity such as lifting something heavy - see "anaerobic".
  • Treatment for varices where a solution is injected into them during an endoscopy.
  • Testing for the presence of condition or the genes for a condition.
  • A bracelet available to buy containing your personalised medical information and emergency contact numbers.
  • Small, broken veins under the skin which can look like red spiders.
  • An organ which removes old blood cells. Its blood supply is connected to the liver.
  • Enlarged spleen.
  • Blood test which measures how much conjugated and unconjugated bilirubin is in the blood.
  • Blood clot in a vein or artery.
  • Abbreviation for temperature, pulse and respiration.
  • A surgically inserted tube placed in the windpipe which can be connected to an oxygen supply and mechanical ventilator.
  • Type of fat.
  • Our figures for the number of people diagnosed in the UK with each GSD are our best estimates. These are based on: • Various incidence rates published by medical sources. • An AGSD-UK audit of English NHS specialist centres. • Our own figures from members and people registered with us.• Our(...)
  • USS, scan which takes images of organs and blood vessels.
  • Veins in the intestine, oesophagus and stomach which can be enlarged and swollen due to portal hypertension. May bleed if not treated.
  • A lab test that measures the number of virus particles in a millilitre of blood.
  • Cholesterol deposited under the skin, can look like pale warts.