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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Williams syndrome (WS) is a rare congenital disorder with distinctive craniofacial features, cardiovascular abnormalities, mental retardation, and behaviour characteristics. The purpose of this study was to investigate the size and morphology of the sella turcica on profile cephalograms in a group of individuals with WS. The material consisted of radiographic cephalograms of 62 Norwegian children, adolescents, and adults with an age range of 4.7-44.4 years. The length, depth, and diameter of the sella turcica were measured and the mean values were compared with normal reference material from the Oslo University Craniofacial Growth Archive. In total, the two-dimensional size of the sella turcica in the WS group was smaller in length, depth, and diameter compared with the control group, but only occasionally reached a significance level of 5 per cent (Student's t-test). The morphology of the sella turcica was assessed and five different morphological types were identified; oblique anterior wall, extremely low sella turcica, sella turcica bridging, irregularity (notching) in the posterior part of the dorsum sellae, and pyramidal shape of the dorsum sellae. The occurrence of these morphological types was more frequent in the WS subjects compared with the reference material, except for sella turcica bridging, which was equally frequent. The females with WS had more dysmorphic sella turcicas than males. This study has demonstrated morphological aberrations in the sella turcica in Norwegian individuals with WS, which should be further elucidated in future research and combined with neurological andendocrinological investigations.
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PMID:Post-natal size and morphology of the sella turcica in Williams syndrome. 1565 71

Williams syndrome (WS) is a rare congenital neurodevelopmental disorder with distinctive facial features, cardiovascular abnormalities, short stature, mental retardation, and behaviour and cognitive characteristics. The aim of this study was to describe the neurocranial morphology and growth in a group of 62 individuals with WS. The neurocranium was analysed on lateral cephalograms and comparisons were made with neurocranial standards from longitudinal data derived from the Oslo University Craniofacial Growth Archive. The size and morphology of the neurocranium in WS subjects differed from controls. Females as a group showed greater differences than males. The posterior cranial base length was shorter in both WS males and females, and the anterior cranial base length was shorter in WS females whereas it was close to normal in the WS male group. The cranial base angle was, however, not different from the control groups. A flattening was seen in the superior aspect of the parietal bone in both WS males and females. In the posterior part of the neurocranium, the prominence of the occipital bone was larger than in the control groups, which was also reflected in a larger total length of the neurocranium. The thickness of the frontal and occipital bones was considerably greater than in the control group. The deviant size and morphology of the neurocranium in WS subjects was already established in the youngest age group and maintained throughout the observation period. The growth pattern of the neurocranium in WS subjects seemed to be similar to that of the control groups, except in a few individuals.
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PMID:Neurocranial morphology and growth in Williams syndrome. 1574 61

Williams Syndrome (WS) is a neurodevelopment disorder associated with a hemizygous deletion on chromosome 7. WS is characterized with mental retardation, severe visual-spatial deficits, relative language preservation, and excellent facial recognition. Distinctive auditory features include musical ability, heightened sound sensitivity, and specific patterns of auditory evoked potentials. These features have led to the hypothesis that the dorsal forebrain is more affected than the ventral. Previously, we reported primary visual area 17 abnormalities in rostral striate cortex, a region contributing to the dorsal visual pathway. Based on the dorsal-ventral hypothesis, and language and auditory findings, we predicted a more normal histometric picture in auditory area 41. We used an optical dissector method to measure neurons in layers II-VI of area 41 in right and left hemispheres of the same 3 WS and 3 control brains used in the area 17 study. There was a hemisphere by diagnosis interaction in cell packing density (CPD) in layer IV and in cell size in layer III between WS and control brains. Post hoc analysis disclosed in control brains, but not WS, a layer IV left > right asymmetry in CPD, and a layer III left < right asymmetry in cell size. WS brains showed more large neurons bilaterally in layer II and in left layer VI. Histometric alterations in area 41 were less widespread than rostral visual cortex. Also, there was less asymmetry in the WS brain. We interpret layers II and VI differences as reflecting increased limbic connectivity in primary auditory cortex of WS.
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PMID:Relative sparing of primary auditory cortex in Williams Syndrome. 1577 50

Williams syndrome is a rare disorder that was first described in 1961. It is thought to be caused by a microdeletion in the long arm of chromosome 7 at 7q11.23 and is a multisystem, congenital, and panethnic disorder characterized by a number of developmental and physical abnormalities, including congenital cardiovascular abnormalities, mental retardation and neurological features, growth deficiency, genitourinary manifestation, gastrointestinal and musculoskeletal problems, behavioral characteristics, craniofacial features, ophthalmologic features, and dental problems. We describe cases of children with Williams syndrome treated in the department of Pediatric Dentistry of the Hadassah School of Dental Medicine, Jerusalem, Israel. The different treatments rendered to these children are discussed followed by general remarks drawn from those treatments and from a literature review. We conclude that sedation can be helpful in the younger age group to reduce anxiety and uncooperative behavior during minimal dental treatments. Treatment under general anesthesia seems more appropriate for older children and adolescents. Special attention should be given to initial evaluation of these patients, especially because with age aortic stenosis tends to intensify, which together with the progressive renal impairment can escalate blood pressure elevation.
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PMID:Medical considerations in dental treatment of children with Williams syndrome. 1582 80

Mental retardation has been categorized into severe mental retardation where genetics plays a very important role and mild mental retardation, in which genetics in some instances plays a role but in which cultural factors also matter a great deal. The pathogenetic, clinical and behavioral characteristics of genetically determined disorders associated with mental retardation differ greatly-as exemplified by two genetic disorders that have been clarified recently, namely Rett syndrome and the Williams syndrome. In the work-up of the developmentally disabled child, previous studies have shown that genetic studies are of have great importance and high yield. Early biochemical diagnosis in newborn screening has tremendous potential and has been strongly supported by NICHD-the PKU story being so much part of what NICHD has done. We must gain a better understanding of structure/function relationships, which becomes more and more possible with neuroimaging. A better understanding of neural plasticity can lead to correction by early intervention.
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PMID:Genetic causes of mental retardation. 1583 96

Williams syndrome (WMS) is a genetic condition resulting from a hemideletion on chromosome 7 that causes cognitive impairment, and a variety of growth and physical abnormalities. Little is currently known about brain morphology in WMS, although one recent MRI report suggested that the central sulcus was abnormally short on its dorsal end compared to normal IQ controls. We sought to replicate this finding in a group of 28 persons with WMS in comparison to both an age and sex matched normal IQ control group (n = 22). In addition, we sought to test the specificity of this finding by a further comparison to an IQ matched control group (n = 20). Using high resolution isotropic voxel MRI, the dorsal and ventral extension of the central sulcus was traced and the distance from the interhemispheric and sylvian fissures was measured. The dorsal extension of the central sulcus in both hemispheres was significantly more distant from the interhemispheric fissure in WMS compared to the lower IQ group and to the normal control group (p's < 0.001). There was no significant difference between groups in the ventral end of the central sulcus. These results suggest that the abnormal dorsal end of the central sulcus may be a specific characteristic of WMS not shared with general mental retardation or low IQ.
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PMID:Foreshortened dorsal extension of the central sulcus in Williams syndrome. 1587 94

Williams syndrome (WS), caused by microdeletion of some 21 genes on chromosome 7q11.23, is characterized by dysmorphic features, mental retardation or learning difficulties, elastin arteriopathy, and striking neurocognitive and social-behavioral abnormalities. Recent studies of murine knockouts of key genes in the microdeleted region, LIM kinase 1 (LIMK1) and cytoplasmatic linker protein 2 (CYLN2), demonstrated significant functional and metabolic abnormalities, but grossly normal structure, in the hippocampal formation (HF). Furthermore, deficits in spatial navigation and long-term memory, major cognitive domains dependent on hippocampal function, have been described in WS. We used multimodal neuroimaging to characterize hippocampal structure, function, and metabolic integrity in 12 participants with WS and 12 age-, sex-, and IQ-matched healthy controls. PET and functional MRI studies showed profound reduction in resting blood flow and absent differential response to visual stimuli in the anterior HF in WS. Spectroscopic measures of N-acetyl aspartate, considered a marker of synaptic activity, were reduced. Hippocampal size was preserved, but subtle alterations in shape were present. These data demonstrate abnormalities in HF in WS in agreement with murine models, implicate LIMK1 and CYLN2 in human hippocampal function, and suggest that hippocampal dysfunction may contribute to neurocognitive abnormalities in WS.
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PMID:Functional, structural, and metabolic abnormalities of the hippocampal formation in Williams syndrome. 1595 40

A case with de novo interstitial deletion of chromosome 7q21.1-q22: A patient with multiple congenital anomalies was found to have a de novo proximal interstitial deletion of chromosome 7q21.1-q22. The patient was 10.5 years of age, and manifestations include growth retardation (below 3rd percentile), mental retardation, mild microcephaly, hypersensitivity to noise, mild spasticity, short palpebral fissures, alternant exotropia, compensated hypermetropic astigmatism, hypotelorism, hypoplastic labia majora and minora, clinodactyly of fingers 4 and 5. Molecular studies revealed that the deletion had a paternal origin, while chromosomes of both parents cytogenetically were shown to be normal. Molecular, and fluorescence in situ hybridization (FISH) analyses confirmed no deletion at the Williams-Beuren Syndrome region. Some of the heterogeneous clinical findings were consistent with previously reported cases of same chromosomal breakpoints.
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PMID:A case with de novo interstitial deletion of chromosome 7q21.1-q22. 1608 Feb 95

In this two-part study, we assessed musical involvements in two samples of persons with Williams syndrome compared to others with mental retardation and also related musicality to anxiety and fears in Study 2. Relative to others with mental retardation, those with Williams syndrome were more likely to take music lessons, play an instrument, and have higher ratings of musical skills. In the Williams syndrome groups only, fewer externalizing symptoms were associated with listening to music, whereas less anxiety and fewer fears were associated with the frequency, duration, and skill in producing music as well as emotional responses to negatively toned music. Implications are discussed for future research on musical processing, musical interventions, and well-being in Williams syndrome and other groups.
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PMID:Music and anxiety in Williams syndrome: a harmonious or discordant relationship? 1608 Jul 73

We examined implicit and explicit memory in adults with Williams syndrome. An age-related dissociation was found; repetition priming (reflecting implicit memory) did not show change with age, but free recall (reflecting explicit memory) was markedly reduced. We also compared the performance of adults with Williams syndrome to adults with Down syndrome and those with unspecified mental retardation. A similar dissociation was observed in adults with Down syndrome but not in adults with unspecified mental retardation. An IQ-related dissociation was also found. Implicit and explicit memory, therefore, show different degrees of association with age and IQ, supporting theories of these memory processes. Results also suggest that Williams syndrome, similar to Down syndrome, may be associated with precocious aging, resulting in the loss of some cognitive abilities.
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PMID:Repetition priming in adults with Williams syndrome: age-related dissociation between implicit and explicit memory. 1621 50


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