Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.8 (hypoxanthine-guanine phosphoribosyltransferase)
 2,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two Korean siblings with partial hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency are reported. The index patient was a boy aged 9 years 10 months who developed acute renal failure with a serum uric acid level of 25.9 mg/dl, after vomiting. The younger brother was asymptomatic but had elevated serum uric acid (9.4 mg/dl). The red blood cell HPRT activity of both siblings was one-tenth of normal. Analysis of genomic DNA revealed a point mutation from A (adenine) to G (guanine) at nucleotide position 215 on exon 3; this is a new mutation. The younger brother had the same mutation and the mother was heterozygous for this mutation.
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PMID:Partial hypoxanthine-guanine phosphoribosyl transferase deficiency in two Korean siblings--a new mutation. 813 95

A 32-year-old man who had had frequent gouty arthritis over the past 17 years, was admitted for acute renal failure. Acute renal failure was improved rapidly after medication was resumed and the patient was sufficiently hydrated. The hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity in the patient had been reduced to about 30% of the normal control. Therefore we considered that this patient suffered from a partial deficiency of HPRT. A point mutation of HPRT gene 68G (guanine) to T (thymine) was detected. This is a mutation that has not been previously reported. Familial analysis indicated that his mother and sister were heterozygotes.
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PMID:Partial deficiency of hypoxanthine-guanine phosphoribosyltransferase manifesting as acute renal damage. 986 46

A male child, who presented at the age of 3.5 years with acute renal failure, was diagnosed as having partial deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT; EC 2.4.2.8). The underlying HPRT mutation was unique in that the specific activity of HPRT in erythrocyte and in fibroblast lysates was normal, but the rate of uptake of hypoxanthine into nucleotides of intact cultured fibroblasts was markedly reduced (23% of normal). The low functioning of HPRT in the intact fibroblasts was associated with decreased utilization of endogenously generated hypoxanthine and with decreased utilization of the cosubstrate 5-phosphoribosyl-1-pyrophosphate (PRPP). The non-utilized hypoxanthine was excreted into the incubation medium. The accumulation of PRPP was indicated by the 2.3-fold increase in the rate of uptake of adenine into intact cell nucleotides and by the 7. 5-fold enhancement of the rate of de novo purine synthesis. Kinetic studies of HPRT activity in fibroblast lysates revealed reduced affinity of the enzyme for PRPP (apparent K(m) 500 microM in comparison to 25 microM in control lysates), manifested in low activity at low (physiological), but not at high PRPP concentrations. The apparent K(m) for hypoxanthine was normal (23 microM in comparison to 14.2 microM in control lysates). With allopurinol treatment, our patient has had no problems since presentation, and is developing normally at 5 years of age.
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PMID:Kelley-Seegmiller syndrome due to a unique variant of hypoxanthine-guanine phosphoribosyltransferase: reduced affinity for 5-phosphoribosyl-1-pyrophosphate manifested only at low, physiological substrate concentrations. 1065 89

Hyperuricemia and secondary urate nephropathy are uncommon in the paediatric setting outside of tumour lysis syndrome. We describe the case of a 12-year-old boy who presented at 3 years of age with acute renal failure. The cause of this remained unknown until the development of uric acid renal calculi 9 years later. This, and the availability of the previously unknown family history, provided the subsequent diagnosis of partial hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency. Detailed family history is important for early detection of this heterogeneous group of disorders. Early treatment may minimise long-term renal morbidity and mortality from renal insufficiency.
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PMID:Partial hypoxanthine-guanine phosphoribosyltransferase deficiency presenting as acute renal failure. 1624 Jan 58

Lesch-Nyhan disease (LND) is a rare X-linked recessive disorder caused by virtually complete deficiency of activity of the purine salvage enzyme hypoxanthine phosphoribosyltransferase (HPRT; EC 2.4.2.8). Human HPRT is encoded by a single structural gene located on the long arm of the X-chromosome (Xq26). The classical LND phenotype occurs almost exclusively in males, manifested in excessive purine production and characteristic neurological manifestations, including compulsive self-mutilation, choreoathetosis, spasticity, and occasionally developmental delay. Heterozygous females are usually phenotypically normal, due to the random inactivation of the X chromosome (Lyonization mechanism). However, six females were reported to be affected with the full biochemical and clinical manifestations of LND. All these cases were heterozygous for an HPRT mutation. Absence of transcription of the normal HPRT allele was attributed in all of them to non-random inactivation of the X chromosome carrying the normal allele. Here we describe an additional LND female, who presented with acute renal failure at the age of two months, in whom absence of transcription of the two HPRT alleles occurred due to as yet undescribed mechanism in LND females: the transcription of one HPRT allele was blocked due to a de novo X chromosome-autosome translocation 46,XX,t(X:2)(q26:p25), with a breaking point encompassing the HPRT gene locus, whereas the transcription of the normal allele was inhibited due to non-random inactivation of the second X-chromosome. Cultured fibroblasts from this patient exhibited the biochemical alterations in purine nucleotide metabolism characteristic of male LND fibroblasts.
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PMID:Molecular, biochemical, and genetic characterization of a female patient with Lesch-Nyhan disease. 1634 67

Lesch-Nyhan syndrome is a very rare X-linked recessive disorder caused by mutation in the gene encoding enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). A complete deficiency of HPRT leads to severe purine overproduction and to uric acid renal lithiasis as a consequence. This may be effectively prevented by administration of allopurinol; however, its overdosage may result in xanthinuria and xanthine urolithiasis. We report on a 9-year-old boy with Lesch-Nyhan syndrome who developed acute renal failure due to bilateral staghorn xanthine urolithiasis resulting from long-term treatment with excessive doses of allopurinol. To the best of our knowledge, the presented case is the first one in the literature.
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PMID:Acute renal failure due to bilateral xanthine urolithiasis in a boy with Lesch-Nyhan syndrome. 1677 22

We describe an HPRT deficiency in a 2-month-old child who presented acute renal failure and gout with normal mental and motor development for age. The patient was diagnosed with Lesch-Nyhan disease and showed a new mutation, a deletion of two bases in exon 3 of the HPRT gene (c.269-270delAT).
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PMID:HPRT deficiency in a two-month-old child presenting acute renal failure and gout with a new deletion of two bases in exon 3 of the HPRT gene. 1741 96

An extensive range of molecular defects have been identified in the human mitochondrial genome (mtDNA), many associated with well-characterised, progressive neurological syndromes. We describe a patient who presented to a mitochondrial clinic with progressive bilateral ptosis, external opthalmoplegia and increasing difficulty with walking. He had previously been diagnosed with a dominant, demyelinating polyneuropathy due to PMP22 gene duplication and had also developed gout, presenting in acute renal failure, due to an X-linked recessive HPRT gene mutation. Muscle biopsy revealed many COX-deficient fibres which we show contain high levels of a third genetic defect--a novel, mitochondrial tRNA(Leu(CUN)) (MTTL2) gene mutation.
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PMID:Neuromuscular disease presentation with three genetic defects involving two genomes. 1985 45