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)

Constitutional loss or inactivation of one copy of a tumor-suppressor gene, as exemplified by hereditary retinoblastoma, increases the propensity for malignancies by reducing the number of events necessary for the complete loss of the negative regulatory function. We developed a selectable mutation assay employing a human lymphoblastoid cell line (LCL) derived from a heterozygous carrier of 2,8-dihydroxyadenine urolithiasis, adenine phosphoribosyltransferase (APRT) deficiency, for dissecting the second step in loss-of-function mutations and for determining the potential of physical and chemical agents for producing such mutations. The mode of mutational events arising in the wild-type allele of the functionally heterozygous APRT gene resembled that reported for tumor-suppressor genes in malignancies in that mitotic non-disjunctions or recombinations as well as deletions prevailed. Ultraviolet light (UV) was much less efficient in inducing these types of mutations than ionizing radiation. A group of autosomal recessive cancer-prone diseases, including xeroderma pigmentosum (XP), has been characterized as being more susceptible to genomic insults, owing to some defects in DNA processing, such as replication, repair, or recombination. This increased genomic instability may accelerate the gain-of-function mutation at a proto-oncogene and/or the loss-of-function mutation at a tumor-suppressor gene. XP complementation group A (XP-A) LCLs were extremely sensitive to UV-mutagenesis at the hypoxanthine phosphoribosyltransferase (HPRT) locus even at equicytotoxic doses. Some unique mechanism may operate in UV-mutagenesis in XP-A. We have succeeded for the first time in rendering XP-A cells tumorigenic in athymic mice by applying multiple exposures to UV and subsequent treatment with TPA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular bases for hereditary cancer-prone diseases. 129 55

A 48-year-old man with a history of recurrent urolithiasis and chronic renal failure underwent a nephrectomy for a renal mass. At surgery the mass proved to be a calculus impacted in a dilated calyx. Gross examination of the kidney revealed chalky white deposits in the deep medulla and papillary tips. Histologic examination revealed chronic interstitial nephritis with brown spicules within some tubular epithelial cells and larger deposits of brown crystals within tubular lumina, the interstitium of the medulla, and papillary tips. Polarization microscopy revealed individual crystals scattered throughout the renal parenchyma. Although the arrangement of the crystals was reminiscent of uric acid, and, in fact, a clinical diagnosis of gouty nephropathy was made, x-ray diffraction analysis demonstrated crystals of 2,8-dihydroxyadenine. Enzymatic studies confirmed the complete absence of adenine phosphoribosyltransferase activity in erythrocyte lysates.
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PMID:Renal insufficiency secondary to 2,8-dihydroxyadenine urolithiasis. 151 30

Inherited metabolic diseases resulting in urolithiasis secondary to urinary excretion of insoluble substances are rare but often present as urinary obstruction of renal insufficiency. We herein report a case of partial adenine phosphoribosyltransferase deficiency associated with 2,8-dihydroxyadenine urolithiasis. In family members the propositus and his younger brother are homozygotes for defective APRT genes, and who exhibits the type II phenotype designated APRT*J (Japanese type).
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PMID:2,8-Dihydroxyadenine urolithiasis due to partial deficit in adenine phosphoribosyltransferase: a case report. 160 69

Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis is a rapid and sensitive method to identify point mutations in a given sequence of genomic DNA. We tried to apply the PCR-SSCP to the diagnosis of adenine phosphoribosyltransferase (APRT) deficiency, which is an autosomal recessive hereditary disease leading to 2,8-dihydroxyadenine urolithiasis. Genomic APRT genes, with or without mutations, were amplified and labeled simultaneously with 32P-dCTP by PCR. When run in a 6% polyacrylamide gel containing 10% glycerol, two types of mutant genes, APRT*Q0 and APRT*J, gave bands clearly distinct from those of the respective normal APRT genes. Since heterozygotes as well as homozygotes for these mutant APRT genes can be detected in 2 days, PCR-SSCP should be a valuable method in the diagnosis of APRT deficiency and in screening a large population for APRT mutant genes.
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PMID:[Detection of mutant adenine phosphoribosyltransferase genes by polymerase chain reaction-single strand conformation polymorphism analysis]. 163 17

A new method for the determination of adenine phosphoribosyltransferase (APRT) activity in human erythrocytes is described. APRT activity was assayed by a non-radiochemical method in which adenosine monophosphate (AMP) and AMP metabolites produced from a substrate adenine were converted to inosine by alkaline phosphatase and adenosine deaminase. The inosine thus produced was quantitated by reversed phase HPLC. This method was simple, precise, sensitive and free from interference with other co-existing erythrocyte enzymes. Four patients with 2,8-dihydroxyadenine urolithiasis and others with several disorders in purine metabolism have been studied, showing that the present method is clinically useful for the diagnosis and the evaluation of the severity of some human diseases.
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PMID:A new method for the determination of adenine phosphoribosyltransferase activity in human erythrocytes by reversed phase high performance liquid chromatography. 186 58

An accurate diagnosis of heterozygotes for autosomal recessive disorders with unknown mutations can be difficult. Using a unique phenomenon occurring in vivo, we designed a method for the diagnosis of heterozygotes for adenine phosphoribosyltransferase (APRT) deficiency which makes way for a qualitative distinction between normal and heterozygous subjects. We cultured peripheral blood mononuclear cells with 2,6-diaminopurine, an APRT-dependent cytotoxin, to search for in vivo mutational cells. Fifteen putative heterozygotes examined were found to possess such mutant cells at rather high frequencies; thus, a false negative diagnosis is unlikely. The analysis of genomic DNA in 82 resistant clones from two of the heterozygotes clarified that 64 (78%) had lost the germinally intact alleles. Thirteen members of APRT-deficient families were examined; eight proved to be heterozygotes. Among 425 individuals from two separate residential areas of Japan, two heterozygotes were found. The authenticity of the heterozygosity was validated by two separate methods for the two heterozygotes; hence, a false positive diagnosis can be ruled out. Our data showed a calculated heterozygote frequency of 0.47% (95% confidence limits; 0.05%-1.7%), a value compatible with that (1.2%) calculated from data concerning the incidence of 2,8-dihydroxyadenine urolithiasis. This novel genetic approach for identifying heterozygotes is now being tested to search for other enzyme deficiencies in humans.
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PMID:Diagnosis of heterozygous states for adenine phosphoribosyltransferase deficiency based on detection of in vivo somatic mutants in blood T cells: application to screening of heterozygotes. 199 41

Homozygous deficiency of a purine salvage enzyme, adenine phosphoribosyltransferase (APRT), causes urolithiasis and renal failure. There are two known types of homozygous APRT deficiencies; type I patients completely lack APRT activity while type II patients only partially lack such activity. All type II patients possess at least one APRT*J allele with a substitution from ATG (Met) to ACG (Thr) at codon 136. Type I patients are considered to possess two alleles (APRT*Q0) both of which code for complete deficiencies. Thus, some patients with type II APRT deficiencies may have a genotype of APRT*J/APRT*Q0. As no individuals with such a genotype have previously been identified, we performed extensive analysis on four members of a family by (1) the T-cell method for the identification of a homozygote, (2) the B-cell method for the identification of heterozygotes, and (3) oligonucleotide hybridization after in vitro amplification of a part of genomic APRT sequence for the identification of APRT*J and non-APRT*J alleles. We report here the first evidence that 2,8-dihydroxyadenine urolithiasis developed in a boy aged 2 years with a genotype of APRT*J/APRT*Q0.
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PMID:Identification of a compound heterozygote for adenine phosphoribosyltransferase deficiency (APRT*J/APART*Q0) leading to 2,8-dihydroxyadenine urolithiasis. 222 34

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

We report a case of acquired idiopathic sideroblastic anemia associated with adenine phosphoribosyltransferase (APRT) deficiency. A 72-year-old male had been troubled with urolithiasis since his teens. In 1984, he was referred to us because of chronic renal failure and anemia. He was diagnosed as having sideroblastic anemia and required red cells transfusion regularly. In June 1989, he was admitted to our hospital because of cerebral infarction. Peripheral blood analysis showed pancytopenia. Bone marrow aspiration revealed hypercellularity with 36.2% erythroblasts, and 18.5% ringed sideroblasts of all nucleated cells. According to the FAB classification, a diagnosis of refractory anemia with ring sideroblasts was made. As his urinary stone consisted of 2, 8-dihydroxyadenine by analysis of infrared spectrum, genetic and enzymatic studies were performed. These studies indicated APRT deficiency. He died of pneumonia accompanied with progressive renal failure on August 9, 1989.
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PMID:[Sideroblastic anemia associated with adenine phosphoribosyltransferase deficiency]. 225 60

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


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