Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.4.2.7 (adenine phosphoribosyltransferase)
692 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

APRT deficiency, a new cause of supposed "uric acid" stones in young children may be benign or life threatening. This stresses the importance of early recognition and diagnosis. The renal failure, severe in some instances, is preventable because 2,8-DHA formation, the precipitating factor in all, may be controlled by allopurinol preferably without alkali. A low purine diet is advised. "Uric acid" stones in children should always be subjected to sophisticated analysis, and regarded with suspicion in young adults. Diagnosis from red cell APRT activity will be impossible in transfused subjects.
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PMID:[Uric acid stones in children. Identification and therapy of a newly detected defect of adenine-phosphoribosyltransferase (author's transl)]. 11 67

To the now 17 case reports in caucasian patients of an urolithiasis in a rare purine metabolism disorder 2,8-dihydroxyadeninuria due to missing activity of adenine phosphoribosyltransferase 3 further cases are presented. Firstly, a monozygotic twin pair is afflicted (13-year-old boys). All calculi be composed of pure 2,8-DHA, except a mixed calculus in a 38-year-old man containing of 80% 2,8-DHA and 20% calcium oxalate. The actual literature is reviewed.
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PMID:[Urolithiasis in 2,8-dihydroxyadeninuria: presentation of 3 additional cases]. 223 80

Inherited adenine phosphoribosyltransferase (APRT) has a recessive transmission. When it is very important, adenine can't be restored into nucleic acids pool and will changed into 2,8-dihydroxyadenine (2,8-DHA) by xanthine oxidase. To date in all countries but Japan, 2,8-DHA urolithiasis is observed only into homozygotic subjects with complete APRT deficiency Commonly, its onset is observed in childhood often dramatically. The authors report two new pediatric cases into new french families. First a 8 years old boy with spontaneous elimination of two lithiasis after right lumbar pain. Secondly an infant (nineteen months) who has presented an acute renal failure with anuria. Bilateral lithiasis included into pyelourectal junctions have been pulled out by bilateral surgical pyelotomy. In each case, lithiasis were radiolucent and diagnosis made by ultrasonography. The uric acid metabolism was normal and it is the infra red spectrophotometric study of stones that had recognised the 2,8-DHA component. In the second case, bilateral residual lithiasis have been broken by piezoelectric extra-corporeal lithotripsy with good tolerance and favorable result. The two children received preventive treatment. After 36 and 19 months they have no recurrence. In the literature, the frequency of 2,8-DHA lithiasis is very more low than the theoretical of homozygotics in population (1/100,000). The common confusion with uric lithiasis is one possible explanation. So spectrophotometric study of radiolucent stones was meant to be realised when uric metabolism is not disturbed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[2,8-dihydroxyadenine lithiasis. 2 new pediatric cases of an unknown metabolic deficit. The use of extracorporal lithotripsy]. 238

Inherited adenine phosphoribosyltransferase (APRT) has a recessive transmission. When it is very important, adenine can't be restored into nucleic acids pool and will changed into 2,8-dihydroxyadenine (2,8-DHA) by xanthine oxydase. To date in all countries but Japan, 2,8-DHA urolithiasis is observed only into homozygotic subjects with complete APRT deficiency. Commonly, its onset is observed in childhood often dramatically. The authors report two new pediatric cases in two new french families. First a 8 year old boy with spontaneous elimination of two lithiasis after right lumbar pain. Secondly an infant (nineteen months) who has presented an acute renal failure with anuria. Bilateral lithiasis incluted into pyeloureteral junctions have been pulled out by bilateral surgical pyelotomy. In each case, lithiasis were radioluscent and diagnosis made by ultrasonography. The uric acid metabolism was normal and it is the infra red spectrophotometric study of stones that had recogniseed the 2,8-DHA component. In the second case, bilateral residual lithiasis have been broken by piezoelectric extracorporeal lithotrypsy with good tolerance and favorable result. The two children received permanent preventive treatment. After 36 and 19 months they have no recurrence. In the literature, the frequency of 2,8-DHA lithiasis is very more low than the theorical incidence of homozygotics in population (1/100,000). The common confusion with uric lithiasis is one possible explanation. So spectorophotometric study of radioluscent stones was meant to be realised when uric metabolism is not disturbed. Prevention associates alimentary diet without purins and permanent treatment by allopurinol (10 mg/kg/day in a child). Not used to date, piezo-electric extracorporeal lithotrypsy seems to take a place for treatment of initial, residual or recurrent 2,8-DHA lithiasis like for our young patient.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[2,8-dihydroxyadenine lithiasis. 2 new pediatric cases of this misdiagnosed metabolic abnormality. The value of extracorporeal lithotripsy]. 269 87

We report a case of 2, 8-dihydroxyadenine (2, 8-DHA) urolithiasis. A 39-year-old female was referred to our hospital with the complaint of right flank pain. An X-ray examination showed right hydronephrosis. On May 1986, right percutaneous nephrolithotripsy was performed. Infrared spectroanalysis revealed 2, 8-DHA and calcium phosphate mixed calculus. The adenine phosphoribosyltransferase activity in erythrocytes was partially deficient. Since the operation, 300 mg/day of allopurinol has been administered, and there have been no signs of recurrence.
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PMID:[A case of 2,8-dihydroxyadenine stones with a partial deficiency of adenine phosphoribosyltransferase]. 304 75

This report is concerned with the experience gained with two 2,8-dihydroxyadenine (2,8-DHA) stone patients. When adenine phosphoribosyltransferase (APRT) deficiency is suspected, the risk of stone formation can be detected at an early stage from the crystalline urinary sediment. Infrared spectroscopic analysis of the crystals or of a urinary stone, if present, will confirm the diagnosis. Determination of the APRT activity will facilitate quantification of the enzyme deficiency and elucidation of the hereditary history. 2,8-DHA excretion in the 24-hour urine and its circadian rhythm were determined at 3-hour intervals using a new method of high performance liquid chromatography determination. This method also provides a means of monitoring the effectiveness of allopurinol therapy.
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PMID:2,8-Dihydroxyadeninuria: laboratory diagnosis and therapy control. 317 1

2,8-Dihydroxyadenine (2,8-DHA) lithiasis is a form of kidney stone previously mistaken for uric acid because of identical reactivity in non-specific tests used routinely in stone analysis. Unlike uric acid, the stones crush easily and do not react with uricase. The biochemical basis for the defect is a deficiency of the enzyme adenine phosphoribosyltransferase (APRT). A complete deficiency has been reported in 29 patients from 11 countries. The number of stone formers reported in Japan (10 homozygotes, 16 heterozygotes) Austria (3), and Switzerland (2) suggests more efficient diagnosis in those countries. The defective enzyme in heterozygotes in Japan is a kinetic mutant demonstrable in intact not lysed cells. 20% of APRT-deficient subjects have been asymptomatic. An equal number have presented in acute renal failure, three of whom are now on dialysis. Formation of the nephrotoxic 2,8-DHA can be prevented by allopurinol. This underlines the importance of early diagnosis, since such severe renal damage should be avoidable.
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PMID:2,8-Dihydroxyadenine lithiasis. 378 4

APRT deficiency may be totally benign or life threatening. The importance of early recognition/diagnosis is thus stressed. Urolithiasis (2,8-DHA stones: the precipitating factor in all cases) is treatable. With early recognition and treatment allopurinol without alkali and a diet low in purine homozygotes have remained clinically and biochemically normal to date. 'Uric acid' stones in children must always be suspect and subjected to sophisticated analysis. Diagnosis from red cell APRT activity may also have its pitfalls.
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PMID:Spectrum of 2,8-dihydroxyadenine urolithiasis in complete APRT deficiency. 742 54

Although gout and hyperuricaemia are usually thought of as conditions of indulgent male middle age, in addition to the well-known uricosuria of the newborn, there is much of importance for the paediatric nephrologist in this field. Children and infants may present chronically with stones or acutely with renal failure from crystal nephropathy, as a result of inherited deficiencies of the purine salvage enzymes hypoxanthine-guanine phosphoribosyltransferase (HPRT) and adenine phosphoribosyltransferase (APRT) or of the catabolic enzyme xanthine dehydrogenase (XDH). Genetic purine overproduction in phosphoribosylpyrophosphate synthetase superactivity, or secondary to glycogen storage disease, can also present in infancy with renal complications. Children with APRT deficiency may be difficult to distinguish from those with HPRT deficiency because the insoluble product excreted, 2,8-dihydroxyadenine (2,8-DHA), is chemically very similar to uric acid. Moreover, because of the high uric acid clearance prior to puberty, hyperuricosuria rather than hyperuricaemia may provide the only clue to purine overproduction in childhood. Hyperuricaemic renal failure may be seen also in treated childhood leukaemia and lymphoma, and iatrogenic xanthine nephropathy is a potential complication of allopurinol therapy in these conditions. The latter is also an under-recognised complication of treatment in the Lesch-Nyhan syndrome or partial HPRT deficiency. The possibility of renal complications in these three situations is enhanced by infection, the use of uricosuric antibiotics and dehydration consequent upon fever, vomiting or diarrhoea. Disorders of urate transport in the renal tubule may also present in childhood. A kindred with X-linked hereditary nephrolithiasis, renal urate wasting and renal failure has been identified, but in general, the various rare types of net tubular wasting of urate into the urine are recessive and relatively benign, being found incidentally or presenting as colic from crystalluria. However, the opposite condition of a dominantly inherited increase in net urate reabsorption is far from benign, presenting as familial renal failure, with hyperuricaemia either preceding renal dysfunction or disproportionate to it. Paediatricians need to be aware of the lower plasma urate concentrations in children compared with adults when assessing plasma urate concentrations in childhood and infancy, so that early hyperuricosuria is not missed. This is of importance because most of the conditions mentioned above can be treated successfully using carefully controlled doses of allopurinol or means to render urate more soluble in the urine. Xanthine and 2,8-DHA are extremely insoluble at any pH. Whilst 2,8-DHA formation can also be controlled by allopurinol, alkali is contraindicated. A high fluid, low purine intake is the only possible therapy for XDH deficiency.
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PMID:Gout, uric acid and purine metabolism in paediatric nephrology. 843 71

Adenine phosphoribosyltransferase (APRT, EC 2.4.2.7) deficiency is an enzymopathy of purine metabolism, which is inherited as an autosomal recessive trait. APRT is a salvage enzyme that normally catalyzes the conversion of adenine to adenosine monophosphate. APRT deficiency results in adenine accumulation with oxidation by xanthine dehydrogenase (XDH; EC 1.1.1.204) to 2,8-dihydroxyadenine (2,8-DHA) then excreted in urine. This compound is extremely insoluble and its crystallization can lead to stone formation and renal failure. The diagnosis of the disease is based on stone analysis by infrared spectroscopy or microscopic examination of urine, which may reveal typical 2,8-DHA crystals. The enzyme activity measurements in erythrocyte lysates will identify both homozygotes and heterozygotes for APRT deficiency. Molecular approach can identify mutations which are responsible of this inherited disease. Two types of deficit are commonly distinguished, depending on the level of residual APRT activity: type I, mainly observed in Caucasian subjects, in whom the enzyme activity is undetectable in homozygous patients and type II, found in Japanese patients who are able to form APRT but the enzyme activity is strikingly reduced because a low affinity for phosphoribosylpyrophosphate. The crystallization of 2,8-DHA and subsequent renal damages may be prevented with allopurinol therapy, a xanthine oxidase inhibitor. The role of the laboratory is crucial to detect APRT deficiency and to assess the efficacy of therapy, the objective being to avoid 2,8-DHA crystal formation.
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PMID:[2,8-dihydroxyadenine nephrolithiasis: from diagnosis to therapy]. 1803 2


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