G6PD deficiency

Introduction

G6PD deficiency is an X-linked genetic disorder causing quantitative deficiency in the production of the red cell enzyme glucose-6-phosphate dehydrogenase (G6PD).

G6PD is responsible for protecting red cells from oxidative damage and deficient patients may experience episodes of haemolysis and anaemia in response to oxidative triggers. In the absence of exposure to oxidative triggers, the vast majority of patients are completely asymptomatic and lead completely normal lives.

The condition therefore does not require routine haematological follow up in the absence of complicating factors (e.g. signs of chronic haemolysis).

Possible clinical manifestations of the disorder include:

• Early onset neonatal jaundice
• Acute jaundice or pallor episodes
• Dark urine
• Fever and abdominal pain
• Lethargy/fatigue
• Shortness of breath.

G6PD deficiency is more commonly seen in boys, but may occasionally present clinically in girls if the mutation causes a more marked quantitative deficiency, if there is skewed lyonisation, or if homozygous mutations are inherited.

Pre-referral investigations

• FBP, film review and reticulocyte count
• LFT and bilirubin
• G6PD assay. 

Pre-referral management

If the diagnosis is confirmed by reduced G6PD assay:

• Provide information handout including common oxidative triggers to avoid (fava beans, naphthalene (moth balls), a number of drugs and drug families – see resources at the end of this guideline)
• Counsel patients and families regarding the X-linked nature of the disorder and the implications for future children
• Provide education on clinical signs to watch for that may suggest a haemolysis episode (pallor, jaundice, lethargy, dark urine, fever/abdominal pain) warranting presentation for medical review.

When to refer

Incidentally diagnosed G6PD deficiency does not require referral to Paediatric Haematology.

Referral may be considered in the following specific circumstances:

• Signs or symptoms of chronic haemolysis (chronic anaemia/hyper-bilirubinaemia despite avoidance of triggers)
• Recurrent acute haemolysis episodes (with or without associated faltering growth) .

How to refer

• Routine non-urgent referrals from a GP or a Consultant should go to the Central Referral Service
• Routine non-urgent referrals from a nurse practitioner, non-medical referrers or private hospitals go to the PCH Referral Office
• Urgent referrals (less than seven days) are made via the PCH Referral Office.

Essential information to include in your referral

• All relevant diagnostic results (FBP, reticulocyte count, LFT and bilirubin, G6PD assay result)
• Specific reason why specialist Haematology review is required. 

Useful resources

• Royal Children’s Hospital Melbourne G6PD Fact Sheet: G6PD Fact Sheet - Royal Children's Hospital Melbourne 
• Women’s and Newborn Health Westmead Hospital G6PD Fact Sheet:
• G6PD Factsheet Westmead Hospital Sydney 
• G6PD Deficiency Association website: https://www.g6pd.org/en/Home.aspx 

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