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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lesch-Nyhan disease (LND) is a rare, X-linked genetic disorder that involves the nearly complete absence of an enzyme (hypoxanthine-guanine phosphoribosyltransferase, or HPRT) that is essential for purine salvage. In addition to hyperuricemia, all patients with classic LND suffer from movement disorder and compulsive self-injury, and most have mental retardation. Patients with partial HPRT deficiency (variants) always have hyperuricemia and often have neurologic abnormalities, but do not self-injure and usually are described as having normal intelligence. Here we compare 15 patients with LND to 9 variants and 13 normal adolescents and adults. Testing revealed unambiguous and qualitatively similar cognitive deficits in both patient groups. The variants produced scores that were intermediate between those of patients with LND and normal participants on nearly every cognitive measure. We discuss these findings in terms of what is known about the neuropathology of LND.
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PMID:Neurocognitive functioning in Lesch-Nyhan disease and partial hypoxanthine-guanine phosphoribosyltransferase deficiency. 1177 23

The Behavior Problems Inventory (BPI-01) is a 52-item respondent-based behavior rating instrument for self-injurious, stereotypic, and aggressive/destructive behavior in mental retardation and other developmental disabilities. Items are rated on a frequency scale and a severity scale. The BPI-01 was administered by interviewing direct care staff of 432 randomly selected residents from a developmental center between the ages of 14 to 91 years. For 73% of those selected, at least one problem was endorsed on the BPI-01. A total of 43% showed self-injury, 54% stereotyped behavior, and 38% aggressive/destructive behavior. Confirmatory factor analysis and item-total correlations supported the three a priori factors. Analyses of variance (ANOVA) showed that of the variables age, sex, and level of mental retardation, only the latter had a significant effect on the BPI-01 total score, the SIB subscale score, and the Stereotyped Behavior subscale score. Aggression/destruction was not significantly related to any of the three variables. Individuals with a diagnosis of pervasive developmental disorder had higher scores on all three subscales than those without, whereas residents with a diagnosis of stereotyped movement disorder had higher Stereotyped Behavior scale scores than those without. The BPI-01 was found to be a reliable (retest reliability, internal consistency, and between-interviewer-agreement) and valid (factor and criterion validity) behavior rating instrument for problem behaviors in mental retardation and developmental disabilities with a variety of potentially useful applications. Strengths and limitations of the instrument are discussed.
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PMID:The Behavior Problems Inventory: an instrument for the assessment of self-injury, stereotyped behavior, and aggression/destruction in individuals with developmental disabilities. 1181 69

Since the first description of a creatine deficiency syndrome, the guanidinoacetate methyltransferase (GAMT) deficiency, in 1994, the two further suspected creatine deficiency syndromes--the creatine transporter (CrT1) defect and the arginine:glycine amidinotransferase (AGAT) deficiency were disclosed. GAMT and AGAT deficiency have autosomal-recessive traits, whereas the CrT1 defect is a X-linked disorder. All patients reveal developmental delay/regression, mental retardation, and severe disturbance of their expressive and cognitive speech. The common feature of all creatine deficiency syndromes is the severe depletion of creatine/phosphocreatine in the brain. Only the GAMT deficiency is in addition characterized by accumulation of guanidinoacetic acid in brain and body fluids. Guanidinoacetic acid seems to be responsible for intractable seizures and the movement disorder, both exclusively found in GAMT deficiency. Treatment with oral creatine supplementation is in part successful in GAMT and AGAT deficiency, whereas in CrT1 defect it is not able to replenish creatine in the brain. Treatment of combined arginine restriction and ornithine substitution in GAMT deficiency is capable to decrease guanidinoacetic acid permanently and improves the clinical outcome. The lack of the creatine/phosphocreatine signal in the patient's brain by means of in vivo proton magnetic resonance spectroscopy is the common finding and the diagnostic clue in all three diseases. In AGAT deficiency guanidinoacetic acid is decreased, whereas creatine in blood was found to be normal. On the other hand the CrT1 defect is characterized by an increased concentration of creatine in blood and urine whereas guanidinoacetic acid concentration is normal. The increasing number of patients detected very recently suffering from a creatine deficiency syndrome and the unfavorable outcome highlights the need of further attempts in early recognition of affected individuals and in optimizing its treatment. The study of creatine deficiency syndromes and their comparative consideration contributes to the better understanding of the pathophysiological role of creatine and other guanidino compounds in man.
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PMID:Creatine deficiency syndromes. 1270 24

Creatine deficiency syndromes are a newly described group of inborn errors of creatine synthesis (arginine:glycine amidinotransferase (AGAT) deficiency and guanidinoaceteate methyltransferase (GAMT) deficiency) and creatine transport (creatine transporter (CRTR) deficiency). The common clinical denominator of creatine deficiency syndromes is mental retardation and epilepsy, suggesting the main involvement of cerebral grey matter (grey matter disease). Patients with GAMT deficiency exhibit a more complex clinical phenotype with dystonic hyperkinetic movement disorder and epilepsy that in some cases is unresponsive to pharmacological treatment. The common biochemical denominator of creatine deficiency syndromes is cerebral creatine deficiency which is demonstrated by in vivo proton magnetic resonance spectroscopy. Measurement of guanidinoacetate in body fluids may discriminate GAMT (high concentration), AGAT (low concentration) and CRTR (normal concentration). Further biochemical characteristics include changes in creatine and creatinine concentrations in body fluids. GAMT and AGAT deficiency are treatable by oral creatine supplementation, while patients with CRTR deficiency do not respond to this type of treatment. Further recognition of patients will be of major importance for the estimation of the frequency, for the understanding of phenotypic variations and for treatment strategies.
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PMID:Clinical characteristics and diagnostic clues in inborn errors of creatine metabolism. 1288 68

Stereotypic movements are repetitive patterns of movements whose physiopathology and relations to other neurobehavioural disorders are still only poorly understood. In this paper our aim is to distinguish between primary stereotypic movements, which are the sole manifestation of an anomaly, while the complementary examinations, except for those involving molecular genetics, are normal; associated stereotypic movements, when they meet primary disorder criteria but there are other coexisting independent neurological signs, that is to say, they are neither the cause nor the consequence of the movement disorder; and secondary stereotypic movements, when they are the consequence of a lesion or acquired neurological dysfunction. Examples of primary stereotypic movements include episodes of parasomnia, such as head rocking, in subjects who are otherwise normal, and stereotypic movements due to emotional disorders, severe environmental deprivation or in institutionalised infants. Examples of associated stereotypic movements are those observed in Rett syndrome, in subjects with sensory defects or with mental retardation due to a variety of causes. And as instances of secondary stereotypic movements we have those that can be seen in infinite like syndrome caused by congenital cerebellar lesions. The purpose of the classification is to lay the foundations for the identification of new syndromes, which would without a doubt facilitate research into their physiopathology, their aetiology and the possible therapeutic attitude to be adopted.
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PMID:[Primary versus secondary stereotypic movements]. 1501 Nov 49

One of the most serious and difficult-to-treat conditions in child and adolescent psychiatry is self-injurious behavior (SIB). SIB can be associated with a number of psychiatric disorders, including mental retardation, schizophrenia, borderline personality disorder, pervasive developmental disorders, stereotypic movement disorder, and Tourette's Disorder. A variety of neurosurgical procedures have been used to treat both intractable SIB and severe Tourette's Disorder. Understandably, there are few reports concerning psychosurgery in children and adolescents for any condition or disorder. This report describes the use of cingulotomy and subsequent limbic leucotomy in an adolescent boy with Tourette's Disorder for SIB. His repetitive and medically serious SIB and failure of all other treatments prompted this intervention after careful, comprehensive review and discussion. Following the second surgery, the severity and frequency of his SIB were reduced.
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PMID:Psychosurgery for self-injurious behavior in Tourette's disorder. 1566 44

We report the case of a woman presenting with unusual, symptomatic epilepsy related to a hypothalamic hamartoma, in the absence of mental retardation or precocious puberty. The seizures manifested themselves clinically as characteristic, paroxysmal movement disorders, such as choreic/ballistic movement. This type of phenomenon is rarely of epileptic origin: we thus suggest that the movement disorder observed here could be due to functional disorganization of the basal ganglia network by the epileptic discharge, causing loss of the inhibition of thalamic activity and thus allowing the occurrence of abnormal movements.
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PMID:Ictal movement disorders and hypothalamic hamartoma. 1574 Nov 40

In recent years, three inherited defects in the biosynthesis and transport of creatine have been described. The biosynthetic defects include deficiencies of L-arginine:glycine amidinotransferase and guanidinoacetate methyltransferase. The third defect is a functional defect in the creatine transporter (SLC6A8). Clinical symptoms of the three defects vary in severity, are aspecific and include mental retardation with severe speech delay, autistiform behaviour, and epilepsy. Some patients with GAMT deficiency exhibit a more complex clinical phenotype with extrapyramidal movement disorder. All three defects can be diagnosed by in vivo proton magnetic resonance spectroscopy of the brain, which shows a severe reduction or absence of creatine. Laboratory investigations for the diagnosis start with the analysis of guanidinoacetate, creatine and creatinine in body fluids (plasma and urine). Based on these findings, enzyme assays for AGAT or GAMT, or a creatine uptake assay for the transporter defect can be performed. DNA mutation analysis of the genes involved can prove the defects at the molecular level. To diagnose female patients with SLC6A8 deficiency, mutation analysis may be the only choice.
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PMID:Laboratory diagnosis of defects of creatine biosynthesis and transport. 1616 44

Rhythmic movement disorder (RMD) consists of rhythmic movements (RMs) that occur on falling asleep or during sleep, can involve any part of the body and have a reported frequency ranging from 0.5 to 2 Hz. RMs have been reported to occur in a high proportion of normal children as a self-limiting phenomenon starting and remitting within early infancy. However, there have also been descriptions of forms of RMD occurring against a background of mental retardation or persisting beyond childhood, or having onset in adulthood. So, the occurrence of RMs can be regarded as both a physiological and a pathological phenomenon. The few polysomnographic studies conducted in this field have shown that, in some forms of RMD, RMs are highly linked to arousal fluctuations. However, the mechanisms that underlie the genesis of RMs and are capable of leading to both physiological and pathological patterns of RMs are not fully understood. Here we emphasise the possibility that the central motor pattern generator, recently hypothesised to play a role in the genesis of motor phenomena during sleep in the cases of parasomnia and epileptic seizures, might account for the occurrence of RMs in both physiological and pathological conditions.
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PMID:Rhythmic movements during sleep: a physiological and pathological profile. 1633 93

We reviewed prevalence rates of fragile X mental retardation gene (FMR1) repeat expansions in movement disorder populations. Inclusion criteria included published epidemiological studies from systematic searches of Medline, Pubmed, Cochrane Databases and Web Science. Thirteen cross-sectional studies were carried out between 2003 and 2005. Subjects with ataxia showed higher than expected rates while those with essential tremor and parkinsonism showed lower rates. The heterogeneous design of the studies, inclusion criteria and mean age of subjects may have led to underestimation of FMR1 repeat expansion prevalence rates.
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PMID:Prevalence of FMR1 repeat expansions in movement disorders. A systematic review. 1649 2


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