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)

A syndrome has been observed in a kindred with deficient activity of hypoxanthine-guanine phosphoribosyltransferase in which affected hemizygotes have had mild mental retardation, a spastic gait, pyramidal tract signs, shortness of stature, proximally placed thumbs and clinodactyly of the fifth fingers. Activity of the enzyme was virtually zero in lysates of erythrocytes or hair roots, but in intact fibroblasts, the level of activity was 7.5% of normal, placing this variant in a group distinct from any previously studied. Kinetic studies revealed a Michaelis constant for hypoxanthine that was also different from other enzymes studied. These observations indicate the presence in this kindred of a distinct variant of hypoxanthine-guanine phosphoribosyltransferase.
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PMID:Syndrome of mild mental retardation, spastic gait, and skeletal malformations in a family with partial deficiency of hypoxanthine-guanine phosphoribosyltransferase. 357 27

A young woman with normal gonadal development and mild mental retardation was found to have a small de novo interstitial deletion of most of band Xp21, karyotype designation 46,X,del(X) (pter----p21.3:: p21.1----qter). Replication studies on lymphocytes and skin fibroblasts revealed that in 45% of cells the normal X was late replicating. Somatic cell hybrids between her fibroblasts and HPRT-deficient Chinese hamster cells were obtained and selected for and against retention of the active human X chromosome. In several independent hybrids the deleted X was retained in the active state. Partial ornithine transcarbamylase (ornithine carbamoyltransferase EC 2.1.3.3) (OTC) deficiency was documented by elevated urinary orotic acid excretion and increased serum glutamine after a protein load. This confirms the mapping of the structural gene for OTC to this deletion. Testing of neutrophil function revealed heterozygosity for chronic granulomatous disease (CGD) suggesting that a gene for CGD maps within the deletion. Thus, X inactivation mosaicism is also present in hepatocytes and neutrophilic granulocytes. Random X inactivation in a female with an Xp deletion has not been previously reported. The cells from this patient and the somatic cell hybrids containing her deleted X chromosome in the absence of the normal X provide material for the precise mapping of X linked genes and DNA sequences on the short arm of the human X chromosome.
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PMID:Random X inactivation resulting in mosaic nullisomy of region Xp21.1----p21.3 associated with heterozygosity for ornithine transcarbamylase deficiency and for chronic granulomatous disease. 651 24