Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a patient with the Lesch-Nyhan syndrome we found decreased spinal fluid 5-hydroxyindole acetic acid (5-HIAA), the major metabolite of serotonin, and decreased homovanillic acid (HVA), the major metabolite of dopamine, indicating a decrease in monoamine metabolism. Administration of 5-hydroxytryptophan and carbidopa produced an increase in spinal fluid 5-HIAA, indicating that it might be possible to correct the serotonin deficiency in this syndrome, but there were no changes in the marked mental retardation and neurological deficits. Self-mutilation appeared to be suppressed by therapy but the effectiveness of the drugs decreased with time. There were also changes in the spinal fluid concentration of amino acids that might affect brain protein synthesis. These changes were corrected during administration of 5-hydroxytryptophan and carbidopa.
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PMID:Effects of L-5-hydroxytryptophan on monoamine and amino acids turnover in the Lesch-Nyhan syndrome. 31 82

A case is reported with a syndrome characterized by mental retardation, choreoathetosis, high levels of uric acid and aggressive, selfmutilation behavior, diagnosed as Lesch-Nyhan's syndrome. The most important features are, its appearance confined only to males, the absence of abnormalities along the prenatal and newborn periods, as well as the progressive impairment in the clinical course of the patient. The presence of high blood levels of uric acid which was controlled with the administration of allopurinol, the anemia, treated with ferrous sulfate and the complete absence of the AGPRT enzyme, were the laboratory findings. The clinical, pathophysiological and biochemical aspects of the treatment were also reviewed, as well as the experiences and findings reported in other series. The authors stress the very low frequency of these cases, the importance of making the diagnosis and the exceptional and eccentricity of the features which are part of the syndrome, such as the bites.
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PMID:[Lesch-Nyhan syndrome. Report of a case]. 87 31

The Lesch-Nyhan syndrome is a rare inborn error of purine metabolism associated with hyperuricacidemia, mental retardation, and an insatiable urge for self-mutilation, especially of the extremities. Insensitivity to pain and severe muscle spasms create very difficult management problems, especially for children being cared for at home. Fortunately this syndrome is rare (1 per 380,000 live births). Four known patients are under treatment in Manitoba, of which two brothers are the subject of this study. In general, the medical management of these patients has been unsuccessful, especially in controlling self-mutilation. It therefore was decided to manage these children by the use of mechanical aids. Through the utilization of custom-designed seating devices control of the self-mutilation has been obtained, reducing the burden of family care. It is now possible for the children to attend regular school on a half-day basis. They are also able to engage in community activities without the fear that a mishap will occur when not under the vigilance of the immediate family.
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PMID:Special devices as aids in the management of child self-mutilation in the Lesch-Nyhan syndrome. 113 85

Hypoxanthine-guanine phosphoribosyltransferase (HPRT, EC 2.4.2.8) is a purine salvage enzyme that catalyses the conversion of hypoxanthine and guanine to their respective mononucleotides. Partial deficiency of this enzyme can result in the overproduction of uric acid leading to a severe form of gout, whilst a virtual absence of HPRT activity causes the Lesch-Nyhan syndrome which is characterised by hyperuricaemia, mental retardation, choreoathetosis and compulsive self-mutilation. The HPRT-encoding gene is located on the X chromosome in the region q26-q27 and consists of nine exons and eight introns totalling 57 kb. This gene is transcribed to produce an mRNA of 1.6 kb, which contains a protein encoding region of 654 nucleotides. With the advent of increasingly refined techniques of molecular biology, it has been possible to study the HPRT gene of individuals with a deficiency in HPRT activity to determine the genetic basis of the enzyme deficiency. Many different mutations throughout the coding region have been described, but in the absence of precise information on the three-dimensional structure of the HPRT protein, it remains difficult to determine any consistent correlation between the structure and function of the enzyme.
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PMID:A review of the molecular basis of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency. 148 31

The Lesch-Nyhan syndrome is a rare inborn error of purine metabolism caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), which results in mental retardation with characteristic self-mutilation, spasticity, extrapyramidal signs and hyperuricaemia. The clinical and biochemical findings in an 18-month-old boy, who presented with renal calculi and was shown to have less than 1% of normal HGPRT activity, are reported. The obvious neurological abnormalities had previously been thought to be due to hypoxic-ischaemic encephalopathy. The expected incidence of this disease is much higher than the known number of cases diagnosed.
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PMID:The Lesch-Nyhan syndrome--an under-recognised condition in South Africa? A case report. 156 65

The authors report the second case of a female with typical Lesch-Nyhan syndrome. She exhibited athetoid movement, self-multilation, mental retardation and spasticity. Laboratory investigations revealed hyperuricaemia, hyperuricosuria and decreased erythrocyte hypoxanthine guanine phosphoribosyl transferase activity. She has normal female external genitalia and karyotype. Her parents are non-consanguineous and there is no family member with gout, nephropathy or any psychoneurological disorder. To prevent self-stimulation, it was necessary to fix the patient's upper extremities to the backrest of her wheelchair. The authors also describe an apparatus that limits elbow flexion.
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PMID:A female patient with Lesch-Nyhan syndrome. 161 15

The study comprised two cases (male & female sibs) from one family, with Lesch-Nyhan Syndrome. They were subjected to clinical evaluation, pedigree construction, uric acid estimation in blood, urates in urine, metabolic screening of blood and urine for amino acids, examination of oral cavity, histological studies of the gingiva by light and electron microscopy as well as buccal smear for Barr & Y bodies (for the female). The proband, a six years old female presented with self-mutilation, mental retardation, hyperactivity and aggression. She had bitten her index finger causing amputation of its distal phalanx. On family study her younger brother (9 months) was found to have increased uric acid and less severe neurologic involvement. The serum uric acid level of the affected female was higher. Her Barr body showed normal pattern. Oral cavity examination showed no abnormalities. Histological examination of the gingiva showed macrophages around the blood vessels. Ultrastructural studies showed more or less normal epithelium. There was collection of macrophages around the blood vessels in the sub-epithelial layer, the cytoplasm of these macrophages contained stippled cytoplasmic inclusions. The surrounding connective tissue showed thin collagen fibers with sharp delineation between the epithelial and connective tissue layers indicating poor quality of collagen. There was no histological difference between the hemizygous male and the heterozygous female. The present study indicates heterozygous expression of Lesch-Nyhan Syndrome at both the clinical and the ultrastructural levels in favour of extreme lyonization or X-chromosome deletion in the affected female. Our findings also indicate that ultrastructural studies could be sensitive indicators of abnormal uric acid metabolism. Further studies are needed to compare the phenotypic expression of hemizygotes and heterozygotes with Lesch-Nyhan Syndrome at both the clinical and ultrastructural levels.
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PMID:Heterozygous expression of Lesch-Nyhan syndrome clinical and ultrastructural studies. 213 93

We studied a case of Lesch-Nyhan syndrome with delayed onset of self-mutilation. Athetotic cerebral palsy and mental retardation were diagnosed at 1 year old, but the disease was not suspected until age 8 years when he began biting his lips and fingers. There was no obvious alteration of catecholamine in urine and CSF. We attempted to induce a series of blink reflexes by electric, mechanical and photic procedures. The R1 amplitude increased and the latency of the R2 shortened compared with controls. This shows that not only orbicularis motoneuron itself, but also uncrossed interneurons, are in a state of hyperexcitability. The contralateral R2 was poor which was in favour of hypoexcitability of the crossed interneurons at the brainstem. The significant large response was obtained by photic procedure which was in favour of hyperexcitability of the motoneurons. Therefore, it is demonstrated that a thorough examination of blink reflexes provides a useful method for examination of a state of the underlying neural activity.
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PMID:Lesch-Nyhan syndrome with delayed onset of self-mutilation: hyperactivity of interneurons at the brainstem and blink reflex. 232 43

We studied 5 boys, 2 to 10 years old, with marked or complete deficiency of hypoxanthine-guanine phosphoribosyltransferase and Lesch-Nyhan syndrome with varying degrees of mental retardation, dysarthria, chorea, dystonia, spasticity, and ataxia. Four patients had marked reduction of homovanillic acid in the cerebrospinal fluid (CSF) and all showed low CSF 3-methoxy-4-hydroxy phenylethylene glycol, indicating reduced dopamine and norepinephrine turnover. Three patients showed high CSF 5-hydroxyindoleacetic acid, suggesting increased serotonin turnover. Some patients improved with carbidopa-levodopa, but others benefited from tetrabenazine, a monoamine-depleting agent. This study provides support for the theory of abnormal central monoamine metabolism in Lesch-Nyhan syndrome.
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PMID:Lesch-Nyhan syndrome: a study of motor behavior and cerebrospinal fluid neurotransmitters. 245 72

When tested in rats supersensitive to dopamine agonists, the atypical neuroleptic clozapine displayed pharmacological properties expected of both a D-1 and D-2 receptor antagonist. The locomotor response induced by the D-1 receptor agonist SKF-38393 in neonatal-6-hydroxydopamine (6-OHDA)-lesioned rats was reversed in a dose-related fashion, although a complete blockade of this behavior was not observed indicative for only a partial antagonism of D-1 receptor function. Clozapine also blocked the self mutilation resulting from L-dihydroxyphenylalanine (L-DOPA) administration to neonatal-6-OHDA-lesioned rats, an effect previously linked to D-1 receptor activation. At higher doses, clozapine blocked the locomotor activity elicited by the D-2 agonist LY-171555 in adult-6-OHDA-lesioned rats. Therefore, the action of clozapine on D-1 as well as D-2 receptor-mediated behaviors contributes to its pharmacological effects. The ability of clozapine to stop self-mutilatory behavior in neonatal-6-OHDA-lesioned rats suggests that this drug might be an effective treatment for self-injurious behavior associated with the Lesch-Nyhan syndrome and mental retardation.
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PMID:Clozapine antagonism of D-1 and D-2 dopamine receptor-mediated behaviors. 249 73


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