Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00492 (hypoxanthine-guanine phosphoribosyltransferase)
 2,385 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A now 45-year-old man with marked chronic tophous gout and recurrent nephrolithiasis has been followed for 12 years. First gouty symptoms appeared at age 18. Uric-acid reducing treatment freed the patient of symptoms, and bony and soft-tissue tophi in part regressed. The early onset and high urinary uric-acid excretion indicated increased uric-acid production. Decreased activity of the enzyme hypo-xanthine-guanine-phosphoribosyl transferase was demonstrated to be the cause of the hyperuricaemia, which led to an excessive purine synthesis. An almost complete loss of activity of this enzyme is the basis of the Lesch-Nyhan syndrome. In the described patient all of the neurological and behavioural disorders of the Lesch-Nyhan syndrome were absent. A pheochromocytoma was found to be the cause of malignant hypertension, which had been present for many years.
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PMID:[Juvenile gout with decreased activity of hypoxanthine-guanine-phosphoribosyl transferase and pheochromocytoma: partial persistence of tophi despite uric-acid reducing treatment for 12 years (author's transl)]. 66 12

The CT brain scan of a 17-year-old patient with primary hyperuricaemia and mental retardation is presented. The examination demonstrates subcortical and cortical atrophy of the brain. The HGPRTase level was below normal. Clinical evidence of self-mutilation or tophi was not found. This patient's condition was interpreted as an incomplete Lesch-Nyhan syndrome.
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PMID:[Cranial computerized tomography in incomplete Lesch-Nyhan syndrome]. 358 89

A 20-day-old male infant presented with acute renal failure. Three weeks later he developed acutely swollen, hot, red joints and tophi in his hands and feet. The serum uric acid was 2.2 mmol/l (normal 0.13-0.23 mmol/l) and the urinary oxypurine/creatinine ratio was 2.26 mmol (normal < 1.5 mmol). Complete deficiency of hypoxanthine guanine phosphoribosyl transferase (HGPRT) in intact erythrocytes confirmed Lesch-Nyhan syndrome. Neurological development was delayed and self-mutilation was observed at 22 months. Acute renal failure secondary to crystal nephropathy and tophaceous gout are unusual presenting features of this rare condition. This child also had transient neonatal hypothyroidism, which is not a recognized manifestation of the syndrome.
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PMID:Lesch-Nyhan syndrome presenting with renal insufficiency in infancy and transient neonatal hypothyroidism. 815 15

Congenital deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) results in a spectrum of clinical phenotypes. All of these phenotypes are associated with marked overproduction of uric acid and related problems such as hyperuricemia, urate nephrolithiasis, tophi, and gout. The mildest phenotypes include only problems related to overproduction of uric acid. The most severe phenotype is known as Lesch-Nyhan disease, in which the phenotype also includes severe motor handicap, intellectual disability, and self-injurious behavior. In between these two extremes is a continuous spectrum of phenotypes with varying degrees of motor and cognitive handicap but no self-injurious behavior. The pathogenesis of overproduction of uric acid in HPRT deficiency is well-understood, and treatments are available to control it. The pathogenesis of the neurobehavioral problems is less well-understood, and effective treatments for them are lacking.
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PMID:Update on the phenotypic spectrum of Lesch-Nyhan disease and its attenuated variants. 2219 33

Lesch-Nyhan disease and its attenuated variants are caused by deficiency of the purine salvage enzyme, hypoxanthine-guanine phosphoribosyltransferase (HGprt). All patients exhibit excessive production of uric acid, which increases the risk for nephrolithiasis, renal failure, gouty arthritis and tophi. The mildest phenotype includes only problems related to overproduction of uric acid. The most severe clinical phenotype includes prominent neurological abnormalities and the universal feature is self-injurious behavior. In between the mildest and most severe syndromes is a broad spectrum of phenotypes with varying degrees of neurological, neurocognitive and behavioral abnormalities. The effect of HPRT1 gene mutations on residual HGprt enzyme activity is the most relevant factor contributing to disease phenotype. Attenuated clinical phenotypes are associated with residual enzyme function, whereas the most severe phenotype is usually associated with null activity. In cases of gouty arthritis with urate overproduction, a careful evaluation for motor impairments or neurocognitive abnormalities may help to identify attenuated variants of Lesch-Nyhan disease for better management.
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PMID:Genotypic and phenotypic spectrum in attenuated variants of Lesch-Nyhan disease. 2493 28