G6PD genotyping

Purpose of the test

Glucose-6-phosphate dehyrogenase (G6PD) deficiency is the most common human enzymopathy. It is involved in red cell metabolism and a deficiency in this enzyme renders the red cell susceptible to oxidant stress. There are more than 400 variants due to point mutations or deletions of the gene responsible for G6PD, resulting in a reduced activity compared with normal. Nevertheless G6PD deficiency is usually asymptomatic. However the main syndromes that may occur as a result of the deficiency are acute haemolytic anaemia in response to oxidant stress, drugs, fava beans or infections. Neonatal jaundice and rarely a congenital non-spherocytic haemolytic anaemia may result from different types of the enzyme deficiency. G6PD deficiency is mainly seen individuals from West Africa, the Mediterranean, the Middle East and South East Asia. The most common mutations identified are:

Mediterranean 188(TCC;Ser > TTC; Phe)

African 68(GTG;Val > ATG;Met)

African 126(AAT;Asn > GAT;Asp)

These mutations are detected by direct mutation analysis.

Sample Requirements

Volume of blood anticoagulated with EDTA:

Adult (16 years and above) 10-15 mls

Children (2-15 years) 5 mls

Infants (0-2 years) 2 mls

Presence of heparin anticoagulant will inhibit PCR applications.

Clotted samples are unsuitable for DNA analysis.

Storage and Transport

Blood should be stored at 4°C where possible. Send at room temperature by first class post.

If possible, please complete the request form attached and send as a hard copy (do not send electronically) with the sample. This will ensure all relevant information is available and will aid us in processing your test.

PDF Request Form

Download G6PD Genotyping Request Form

Turnaround Time

4 - 6 weeks

Time Limit for Extra Tests

5 years

Factors affecting results or interpretation

Presence of heparin anticoagulant will inhibit PCR applications.

Clotted samples are unsuitable for DNA analysis.

Samples must be clearly labelled with the patients first name, surname, D.O.B, hospital number and the date the sample was taken. The details on the sample must correspond to the request form. Unlabelled samples will not be accepted.