Purine metabolic disorders are often devastating for the patients and their families. About 28 have been identified – some only in the last thirty years – and the incidence overall is estimated at about 2 per million people. Thus many cases remain undiagnosed, or recognised only later in life. You may have patients with the following symptoms:
- Gout in a young man or woman, or a child
- A history of infections that do not respond to treatment
- ‘Gravel’ on a child’s nappy/diaper, passage of small stones or loin pain
Please consider referring such patients to a local specialist in metabolic medicine, who may ask for samples of blood or urine for analysis of uric acid or other diagnostic markers by sensitive chromatography, mass spectrometry or other methods. In some cases, the activity of the relevant enzymes can be measured in the samples.
Early diagnosis can improve the prognosis in most of the purine metabolic disorders. It should be noted that, occasionally, girls may be affected by X-linked disorders such as LNS/LND and PRPS.
- Gout and/or renal failure are associated with primary gout in middle age, and with LNS, PRPS, FJHN
- Kidney stones are associated with deficiencies of XDH or APRT
- Neurological deficits may be associated with deficiency of ASA, DHPA, DHPD, PNP, XO or HPRT enzymes, or with superactivity of PRPS
- Immunodeficiency may be caused by deficiencies in ADA or PNP or the pyrimidine enzyme UMPS
- Anaemia may result from defects in one of several purine or pyrimidine enzymes
- TMPT is an enzyme that is not normally essential to a healthy life, but if insufficient, it can cause dangerous intolerance to therapy with azathioprine. If TPMT is superactive, azathioprine is not effective. Patients should be tested for TPMT activity so that the correct dose of azathioprine can be prescribed
- Note that treatment with allopurinol may cause kidney damage in young patients with genetic gout.
PUMPA has prepared a series of booklets covering some of the purine metabolic disorders. We aim to provide patients, parents and professionals with the basic facts – the clinical presentation, biochemistry, progression, recent advances in their treatment, and links to further help. We have drawn on the experience of patients, doctors and scientists in the United Kingdom and Europe. The booklets are available from the Secretary (see Contact Us) or you may download the text from the links given below. You may like to donate £5/$8/s€8 per booklet.
These texts (*) contain a diet sheet that summarises the requirements for a low-purine, caffeine-free diet used in the investigation of this disorder.
Please note that many of the contact details in the booklets may now be obsolete. See instead the Useful links section on this website.
‘Gout, answers at your fingertips’by L.G. Darlington, E.A. Carrey, D. Perrett; Second edition 2013 published by Class Publishing (London) Ltd offers a guide to the symptoms and treatment of gout for all patients, including some purine metabolic disorders, and describes recent studies on the influence of diet on developing classical gout.