Causes of hyperuricaemia include:

# Underexcretion :
Renal impairment
Metabolic syndrome
Drugs, e.g. diuretics, low-dose aspirin, cyclosporin, tacrolimus, pyrazinamide, ethambutol, levodopa, nicotinic acid budget-saving wedding collection in vintage style
Acidosis
Pre-eclampsia and eclampsia
Hypothyroidism, hyperparathyroidism
Sarcoidosis
Familial juvenile gouty nephropathy
Chronic lead intoxication
Trisomy 21
Idiopathic.

# Overproduction :
Purine rich diet
Tumour lysis syndrome
HGPRT deficiency (Lesch-Nyhan and Kelley-Seegmiller syndromes)
Increased PRPP synthetase activity
Idiopathic.