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)

To determine whether patients with acquired asplastic anemia (AA) exhibit clonal hematopoiesis, we used restriction fragment length polymorphisms of the X-linked genes phosphoglycerate kinase (PGK1) and hypoxanthine phosphoribosyltransferase (HPRT) and the X-linked probe M27 beta. Of the 19 female patients studied, 18 (95%) patients were informative for at least one marker. Of these, eight patients (42%) were heterozygous for PGK1, two (11%) for HPRT, and 16 (84%) for M27 beta. In 13 (72%) patients, a monoclonal pattern was found. Analysis of purified cell suspensions of four of these patients showed that both myeloid and lymphoid cells were of monoclonal origin, indicating the involvement of an early stem cell. The four patients who were studied at presentation all showed a monoclonal pattern. One of these patients showed a spontaneous recovery despite persistent clonal hematopoiesis. The presence of either clonal or polyclonal hematopoiesis did not show a correlation with the response to antithymocyte globulin (ATG) treatment. A relapse after ATG was also seen in a patient exhibiting polyclonal hematopoiesis. Conversely, a monoclonal pattern did not preclude the occurrence of a partial or complete response to ATG. Other potential markers to study clonality, including cytogenetic abnormalities or point mutations of the N-ras protooncogene, were not found in any of the patients. It is concluded that patients with AA may exhibit clonal hematopoiesis. The significance with respect to evolution to disorders with clonal hematopoiesis like paroxysmal nocturnal hemoglobinuria, myelodysplasia, and acute leukemia remains to be determined.
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PMID:Clonal hematopoiesis in patients with acquired aplastic anemia. 163 35

The clonal composition of each cell population was determined from the characteristic methylation pattern of DNA and the restriction fragment length polymorphism (RFLP) of the hypoxanthine phosphoribosyltransferase (HPRT) and phosphoglycerate kinase (PGK) genes, both located on the X chromosome. About 71% of Japanese females are heterozygous in terms of the RFLP of either HPRT or PGK genes, which was demonstrated by using 5' genomic DNA or cDNA probes for these genes. All 3 cases of chronic myeloproliferative disorders showed monoclonal patterns. AML or ALL cases demonstrated either monoclonal or polyclonal patterns depending upon the percentage of blastic cells. Monoclonal patterns were seen in 3 of 4 cases of myelodysplastic syndromes and both PNH cases.
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PMID:Molecular genetic approach to the analysis of clonal proliferation in hematologic disorders. 257 94

Clonality analysis, by means of polymorphisms of X-linked genes and their methylation patterns, was performed in 41 female patients with various types of refractory anemia. Bone marrow cells, peripheral blood cells, and granulocytic and lymphocytic fractions were analysed by Southern blotting with PGK, HPRT, and M27 beta probes. Clonal hematopoiesis was evidenced in 8 of 19 patients with aplastic anemia, 4 of 6 patients with RA or RARS, 3 of 7 patients with PNH, and 5 of 9 patients whose hematological characteristics did not meet the criteria of either of these entities. For aplastic anemia, clonal hematopoiesis was demonstrated in higher frequency in the patients who had longer history after diagnosis. In refractory anemia, as a whole, no clear correlation was observed between existence of clonal hematopoiesis and morphological characteristics of hematological cells.
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PMID:[Clonality in refractory anemia]. 809 42

Paroxysmal nocturnal haemoglobinuria (PNH) results from acquired mutations in the PIG-A gene of an haematopoietic stem cell, leading to defective biosynthesis of glycosylphosphatidylinositol (GPI) anchors and deficient expression of GPI-anchored proteins on the surface of the cell's progeny. Some laboratory and clinical findings have suggested genomic instability to be intrinsic in PNH; this possibility has been supported by mutation analysis of hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene abnormalities. However, the HPRT assay examines lymphocytes in peripheral blood (PB), and T cells may be related to the pathophysiology of PNH. We analysed the molecular and functional features of HPRT mutants in PB mononuclear cells from eleven PNH patients. CD8 T cells predominated in these samples; approximately half of the CD8 cells lacked GPI-anchored protein expression, while only a small proportion of CD4 cells appeared to derive from the PNH clone. The HPRT mutant frequency (Mf) in T lymphocytes from PNH patients was significantly higher than in healthy controls. The majority of the mutant T lymphocyte clones were of CD4 phenotype, and they had phenotypically normal GPI-anchored protein expression. In PNH patients, the majority of HPRT mutant clones were contained within the Vbeta2 T cell receptor (TCR) subfamily, which was oligoclonal by complementarity-determining region three (CDR3) size analysis. Our results are more consistent with detection of uniform populations of expanded T cell clones, which presumably acquired HPRT mutations during antigen-driven cell proliferation, and not due to an increased Mf in PNH. HPRT mutant analysis does not support underlying genomic instability in PNH.
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PMID:Frequent HPRT mutations in paroxysmal nocturnal haemoglobinuria reflect T cell clonal expansion, not genomic instability. 1508 21