Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P00492 (hypoxanthine-guanine phosphoribosyltransferase)
 2,385 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The brains of two patients with Lesch-Nyhan syndrome (LNS) were studied. The concentration of dopamine was decreased in the caudate nucleus of LNS patients. Immunohistochemical methods revealed that the dopamine (DA) D1 and D2 receptor and methionine-enkephalin immunoreactivities (IRs) were increased in the putamen, and less significantly in the caudate nucleus. The D1 and D2 receptor IRs of the cingulate cortex, the tryptophan-hydroxylase IR in the dorsal nucleus of the midbrain, as well as the substance P and methionine-enkephalin IRs of the nociception-conducting structures, including the periaqueductal gray and spinal trigeminal nucleus, were not changed. Tyrosine-hydroxylase IR was not decreased in the substantia nigra of the LNS patients. Therefore, the cause of the decreased dopaminergic activity in LNS may not be involved in the production of tyrosine hydroxylase in the substantia nigra. Developmental abnormalities due to the DA defect at an early age might exist in the postsynaptic structure in the striatum.
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PMID:Dopamine receptor upregulation in Lesch-Nyhan syndrome: a postmortem study. 1040 87

Working memory has been described as a neurocognitive probe of prefrontal brain functioning. Genetic variability related with catechol-O-methyltransferase (COMT) gene (Val158Met polymorphism) has received increasing attention as a possible modulator of working memory tasks in both schizophrenic patients and healthy subjects, although inconsistencies across studies have been found. This may be related to the existence of different working memory components, processes and modalities, which may have different sensitivities to subtle changes in dopamine levels and, therefore, the effect of the underlying COMT Val158Met genetic variability. To test this out a large sample of 521 healthy individuals from the general population were tested on the WCST and three working memory tasks that cover the assessment of verbal and spatial working modalities as well as different components and processes (Letter and Number Sequencing, CPT-IP, Backwards Visual Span). All individuals were genotyped for the rs4680 (Val158Met) polymorphism at the COMT gene. Met carriers showed near-significant better performance in the LNS compared with Val/Val individuals (F = 3.9, df = 1, P = 0.046). Moreover, the analysis for linear trend found that Met allele carriers showed significantly better performance than Val/Val individuals (B = 0.58 P = 0.031), although evidence for a linear trend was not found. None of the WCST indices differed among genotypes. Consistent with the hypothesis that Val158Met polymorphism (COMT gene) might account for individual differences on dopamine-dependent prefrontally related neurocognitive functions, the Letter-Number Sequencing task, which requires not only maintenance but also active manipulation of information seemed to be more sensitive to the disadvantageous Val/Val genotype in a large non-clinical sample.
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PMID:Putative role of the COMT gene polymorphism (Val158Met) on verbal working memory functioning in a healthy population. 1821 17

Phenylketonuria is a defect in phenylalanine metabolism resulting in the excretion of phenylketones and severe intellectual disability. The principle of eliminating the offending amino acid from the diet as a successful treatment strategy was demonstrated. The development of a low methionine diet to treat homocystinuria was established after identifying the transsulfuration pathway resulting in cysteine synthesis. Both conditions are examples of disorders of amino acid metabolism. Lesch-Nyhan syndrome, a rare disorder of purine metabolism resulting in intellectual disability and self-injurious behavior, is a classical inborn error of metabolism. Disorders of creatine biosynthesis are relatively newly described and less known diseases.
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PMID:Inborn Errors of Metabolism with Cognitive Impairment: Metabolism Defects of Phenylalanine, Homocysteine and Methionine, Purine and Pyrimidine, and Creatine. 2950 13


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