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Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic disorder which causes haemolysis (premature breakdown of red blood cells).
Key points about G6PD enzyme
Key points about the G6PD enzyme:
- It is a cytoplasmic enzyme in the hexose monophosphate pathway responsible for the production of glutathione. It helps to protect the red blood cell from oxidative damage.
- The G6PD gene lies on the X chromosome and over 300 mutations have been described.
- G6PD deficiency is a common X-linked recessive genetic disorder
- It affects:
- 1:50 southeast Asians
- 1:10 Mediterranean families (Italian, Greek and Middle Eastern)
- 1:10 African- American males
- Because of the high gene frequency in some regions, homozygous affected females are not uncommon.
- Females may also be affected through lyonisation or if they have Turner’s syndrome.
Clinical disorders related to G6PD
There are three major clinical disorders caused by G6PD deficiency :
- neonatal hyperbilirubinaemia
- chronic haemolytic anaemia
- induced haemolytic anaemia triggered by exposure to:
- naphthalene (mothballs)
- fava (broad) beans
- viral infections.
Symptoms of G6PD deficiency
Symptoms may include:
- dark coloured urine
- shortness of breath.
However, neonates usually present with jaundice in the absence of anaemia.
Jaundice can be severe and result in kernicterus.
Differential diagnosis of G6PD deficiency
Causes of haemolytic anaemia
Haemolytic anaemia may be caused by:
- maternal-fetal blood group incompatibilities:
- rhesus isoimmunisation
- ABO incompatibility
- other red cell enzyme deficiencies (such as pyruvate kinase)
- red cell membrane disorders (such as hereditary spherocytosis).
- disorders of haemoglobin synthesis (such as alpha thalassaemia group of disorders).
G6PD deficiency should be considered in infants with history of jaundice, anaemia and splenomegaly, especially in those of African or Mediterranean ancestry.
Investigation of G6PD deficiency
Findings that suggest the need for further investigation include:
- unconjugated hyperbilirubinaemia
- Heinz bodies noted on FBE
- increased reticulocyte count
- negative direct anti-globulin titre (Coombs) test.
Diagnosis of G6PD deficiency
G6PD screen then assay.
Management of G6PD deficiency
- avoiding oxidative stressors
- rarely anaemia may be severe enough to warrant blood transfusion
- treating hyperbilirubinaemia with:
- exchange transfusion may be required at a lower threshold if active haemolysis
- confirmation of diagnosis
- educating parents about G6PD deficiency and how to avoid triggers (especially mothballs)
- recommending testing of other children in the family if not already done.
- Medline plus glucose-6-phosphate dehyrogenase deficiency
- RCH - Kids Health Info
- Parent information sheet
- Balnchette V, Doyle J, Schmidt B, Zipursky A. Hematology. In Neonatology: Pathophysiology and Management of the Newborn, 4th ed. Philadelphia: JB Lipincott Co 1994; 952-999
- Jennifer E Frank, Diagnosis and Management of G6PD Deficiency Am Fam Physician, 2005,Oct 1;72(7):1277-1282
Last updated 17 Sep 2018
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First published: October 2013
Last web update: October 2018
Review by: March 2020
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Page last updated: 17 Feb 2021