Glucose-6-Phosphate Dehydrogenase Deficiency

What else is it called?

  • Deficiency of glucose-6-phosphate dehydrogenase
  • G6PD deficiency
  • G6PDD
  • Glucose 6 phosphate dehydrogenase deficiency

Get in touch

Contact our caring team on 08452 412 173 for help and support. Our phone lines open 10am-4pm, Monday to Friday.

Prefer to email? Our email address is

What causes it?

Glucose-6 phosphate dehydrogenase deficiency is caused by a genetic defect to the G6PD gene which produces the G6PD enzyme, this enzyme breaks down carbohydrates. G6PD is also responsible for producing the substance NADPH which is an important co-factor of metabolism and is involved in the protection of your red blood cells. When the body cannot cope with the accelerated loss of red blood cells, this is when anaemia occurs.

How common is it?

It has been reported that approximately, 400 million people have been diagnosed with this metabolic condition. This condition is more commonly diagnosed in males, with estimates of a 1 in 10 diagnosis in African American males.

This condition affects all races, but it is most common in those of African, Asian or Mediterranean descent. Symptoms tend to be milder in those of African origin and more severe in those of a Mediterranean race

What are the signs and symptoms?

Some individuals diagnosed with this metabolic condition do not present any symptoms. Symptoms are usually specific to the individual, however, the main symptom of Glucose-6 phosphate dehydrogenase deficiency is hemolytic anaemia. This is where the body destroys red blood cells quicker then it can form them. Symptom of a hemolytic episode are identified by paleness in the skin, yellow skin or eyes (Jaundice), fatigue, an enlarged spleen, a rapid heartrate and dark coloured urine (it can appear red and even black. Symptoms usually occur when you are subjected to a viral or bacterial infection, stress or are taking certain medications.

Sudden hemolytic episodes can be fatal, they can be caused by changes in medication, eating certain types of foods such as fava beans or certain types of infectious diseases. Sudden hemolytic anaemia from eating fava beans (favism) can be rapid. Favism can occur at any age but occurs more often and more severely in children. A hemolytic anaemia episode may be preceded by behavioural changes such as irritability or lethargy.

Skin ulcers are a rare symptom of this condition, but they can present with the more severe form of this condition.

How is it diagnosed?

Glucose-6 phosphate dehydrogenase syndrome may be diagnosed by a CBC blood test. This blood test is undertaken to identify any abnormalities within the systems of the body. Your health care professional (usually a phlebotomist) will insert a small needle into the vein in your arm to gain a blood sample to then test for this condition.

A reticulocyte count may also be undertaken by your health care professional. This is to identify the number of immature red blood cells that are being produced by the body. Again, the same method for a blood test would apply for this testing.

A urinalysis may also be performed to check the colour of your urine as well as to see if it contains the correct level of by-product made by the body.

Can it be treated?

Treatment for Glucose-6 phosphate dehydrogenase syndrome is to avoid instances that may trigger an offset of symptoms. Treatment may involve prescribing medication to treat infections, stopping drugs that are causing the destruction of these red blood cells and possible blood transfusions to gain a balance between the red blood cell turnover and the ones that are being produced.

Avoidance of chemicals that caused oxidative stress for this condition is recommended. Oxidative stress occurs when there is an imbalance between free radicals and antioxidants. If there are more free radicals in your body then there are antioxidants then these molecules can react with fat, protein or with your DNA and they can cause damage to them. Avoidance of substances contain these molecules helps to avoid the risk of red blood cells being broken down due to free radical damage. Substances that causes oxidative stress can be, high sugar and processed food, cigarettes, exhaust fumes, overdosing on paracetamol and can be avoided by having a healthy diet with foods full of antioxidants and undertaking exercise.

Do my family need to be tested?

Glucose-6 phosphate dehydrogenase syndrome is inherited in an X-linked chromosomal manner. This means that one of the X linked sex chromosomes that you inherited has the disorder upon it. With males who only have one of the X Sex linked chromosomes, one altered copy of the G6PD gene is enough for symptoms to present. Whereas with females who have two copies of the G6PD gene on the two copies of the X sex linked chromosomes, the person may have a non-functioning G6PD gene on one of the chromosomes, but the other X chromosome may be able to provide instructions to make substancealpha-galactosidase A and thereby the symptoms would not present or be less severe.

However, when symptoms do present these can cause nervous system issues, chronic pain and generally woman with this condition are at increased risk of high blood pressure and stroke.

Males with Glucose-6 phosphate dehydrogenase syndrome pass their X chromosome on to all their daughters. In this way, all daughters of affected males will have the gene for Fabry disease. This is assuming paternity is not of concern or in question. However, symptoms may not present as the X chromosome inherited from the mother may be able to make up for the non-functioning or absent one.

Every time a female has a child there is a 50% chance that they will pass the metabolic condition onto their daughter and a 50% chance that you will not. Fathers do not pass the gene onto their sons as they only inherit the Y chromosome from their father.

There is nothing either parent can do, before or during a pregnancy, to cause a child to have this condition.

Once you are diagnosed, you can speak to a genetic counsellor. They can explain how you may have inherited Fabry disease. They can also tell you about genetic testing for the rest of your family. They can provide advice and support if you go on to have children of your own.

Diagram showing the autosomal recessive inheritance pattern.


Relevant Organisations


References are available on request. Please contact us by phoning 0845 241 2173 or emailing [Resource Library No: GNM039].

Skip to content