PNP (Purine nucleoside phosphorylase) enzyme assay

Purine nucleoside phosphorylase (PNP) deficiency catalyses the conversion of the purine nucleosides inosine, deoxyinosine, guanosine and deoxyguanosine to the respective bases. The enzyme is assayed in red cell lysates using inosine as the substrate with products of the reaction separated from substrate by HPLC.
Clinical details: 
Inherited severe combined immunodeficiency. Children typically present with recurrent infections due to absent T-cell immunity. There may be B-cell dysfunction leading to autoimmunity. Neurological abnormalities are present in about 50% of patients. Uric acid in plasma may be low, but not always. The disorder is autosomal recessive.
Reference range: 

3000 - 7000

Sample type and Volume required: 
4 mL blood EDTA (purple top)
Turnaround time: 
1 week
Storage and transport: 
Store in fridge, ( don’t freeze)to lab within 3 days/1st class pos
Purine Research Laboratory at St Thomas'
020 7188 1266
St Thomas’ Hospital
North Wing - 4th Floor
Westminster Bridge Road
London SE1 7EH
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 15/12/2015