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

Among congenital defects the most common are the congenital heart defects, which constitute a heterogeneous group with a multifactor etiology. A single gene mutation has been identified in some of them, such as in of Williams's syndrome, or they can be due to teratogenic agents. The advance in diagnosis and treatment of congenital heart defects has become very important because mortality has diminished and patients live longer and better, reaching adult hood. Molecular biology offers now opportunities understand the cause of many genetic diseases thanks to molecular studies of chromosomes. Conotruncal malformations are known to be caused by a microdeletion in chromosome 22(22q11), this mutation is also responsible for the DiGeorge and cardiovelofacial syndromes, the most relevant aspects are: congenital heart disease, which is present in 75% of the cases, the leading disorder is Fallot's tetralogy with pulmonary atresia, in second place is interruption of the aortic arch type B, followed by common truncus arteriosus. These patients have other phenotypic features, such as high palate, speech problems, malimplantation of ears, and protuberant nose tip, among others. Diagnosis is made with the FISH (fluorescent in situ hybridization) test that shows a microdeletion in chromosome 22 at the 11.2 region. Another syndrome that has received great attention is the Williams-Beuren syndrome, which courses with mental retardation, hypercalcemia, characteristic facies, and supravalvular aortic and pulmonary stenosis. To day, it is known that its cause is a deletion in chromosome 7(7q11.23), which affects elastin region, in consequence, affecting the vessels.
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PMID:[Congenital cardiopathies and syndromes in adults]. 1200 67

This study examined the use of emotional and informational aspects of language in populations that demonstrate developmental social-emotional and linguistic pathologies. We tested high-functioning autistic (HFA) individuals because this group reveals deficiencies in social-emotional and informative aspects of language as well as abnormalities in sociability. We tested Williams syndrome (WS) individuals because of the claim that the social-emotional aspects of language use and sociability are differentially preserved in the context of mental retardation. We compared the performance of these two groups with two groups of control children (7- and 11-year-olds). All of the participants viewed a slide show depicting an event and were asked to retell the story. These narratives were coded for emotional and informational elements. The results showed that on measures of emotional elements, the WS group patterned with the control groups and only the HFA participants received lower scores, while on the informational elements, the two pathological groups did not differ, and both were lower than the controls. The results suggest that the preservation of language among WS individuals is specific for the emotional aspects of language.
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PMID:Narrative analysis in developmental social and linguistic pathologies: dissociation between emotional and informational language use. 1203 Apr 95

There are limited population-based data on the occurrence of Williams syndrome. We estimated its prevalence combining data from two investigations. One was an epidemiologic study originally designed to assess the prevalence and etiology of mental retardation among 30,037 Norwegian children born between 1980 and 1985 and living in Akershus County on January 1, 1993. The other investigation was a national survey of Williams syndrome. In the first study, 213 children were referred for evaluation, whereas the second study comprised 57 cases with Williams syndrome born between 1970 and 1992, who were referred for evaluation from all Norwegian counties. The epidemiologic study revealed three children with Williams syndrome, whereas one additional case complying with our demographic criteria was identified in the national survey, thus giving a prevalence of 1 in 7500. In all cases, a typical chromosome 7q11.23 deletion was detected. We also conclude that Williams syndrome is not an uncommon cause of mental retardation, with a prevalence of approximately 6% of patients with genetic etiology.
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PMID:Prevalence estimation of Williams syndrome. 1208 82

Piccolo belongs to a family of presynaptic cytoskeletal proteins likely to be involved in the assembly and function of presynaptic active zones as sites of neurotransmitter release. Given that abnormalities in the formation of synaptic junctions are thought to contribute to cognitive dysfunction during brain development, we have analyzed and compared the gene structure of the Piccolo gene, PCLO, from humans and mice and determined their chromosomal localization. A comparison of the deduced amino acid sequence of cDNA clones encoding Piccolo from human, mouse, rat and chicken reveals the presence of distinct homology domains. Only subsets of these are also present in the structurally related active zone protein Bassoon indicating that Piccolo and Bassoon perform related but distinct functions at active zones. Characterization of the PCLO gene reveals the presence of 25 coding exons spread over 380kb of genomic DNA. The human PCLO gene maps to 7q11.23-q21.3, a region of chromosome 7 implicated as a linkage site for autism and Williams Syndrome suggesting that alterations in the expression of Piccolo or the PCLO gene could contribute to developmental disabilities and mental retardation.
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PMID:Gene structure and genetic localization of the PCLO gene encoding the presynaptic active zone protein Piccolo. 1217 52

Williams syndrome (WS) is the result of a hemideletion of about 17 genes in the q11.22-23 region of chromosome 7. Patients with WS show unique phenotypic features that include elfin face, heart malformations, calcium metabolism problems and learning disorders. The latter consist of mental retardation that is characterised by serious difficulties with processing visuospatial tasks, a striking ability to easily recognise faces, a relatively developed linguistic capacity and sensitiveness to sound, a strong need to establish affective ties with other people and a fondness for music. Anatomical studies show a decrease in the postero-dorsal parts of both hemispheres of the brain, malformation in the central dorsal region and an expansion of the superior temporal gyrus, of the amygdala and of the frontal lobe. These macroscopic anomalies are accompanied by microscopic anomalies, which consist of changes in the number and size of the neurons. Studies on evoked potentials show acoustic hyperexcitability and abnormal waves related to language and to faces. Genetic studies in our laboratories show that the exact size of the deletion can vary, which means partial cases also exist and have partial phenotypes. Combining behavioural, electrophysiological, anatomical and genetic reports suggests a problem with the posterior dorsal region of the brain, possibly resulting from mistakes in establishing the dorsoventral and caudorostral genetico-molecular gradients, which specify the cortical regions during development.
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PMID:[Williams syndrome. A summary of cognitive, electrophysiological, anatomofunctional, microanatomical and genetic findings]. 1259 14

Williams syndrome is a genetic disorder associated with characteristic facies, supravalvar aortic stenosis, peripheral pulmonary stenosis, mental retardation, hypertension, premature aging of skin, and congenital cardiac defects. Many cardiac defects such as bicuspid aortic valve, mitral valve regurgitation, coarctation of the aorta, and ventricular or atrial septal defects are linked to the syndrome. Complete atrioventricular septal defect has rarely been associated with Williams syndrome and only one necropsy case has been reported in the literature. The long term follow up of Williams syndrome associated with complete atrioventricular septal defect is reported. During a 10 year follow up period, the pressure gradient in the ascending aorta did not increase despite narrowing of the ascending aorta as identified on an aortogram.
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PMID:Williams syndrome associated with complete atrioventricular septal defect. 1269 80

A group of adolescents with Williams syndrome (WS) was compared to matched groups of adolescents with Prader-Willi syndrome and nonspecific mental retardation on a task that tested the ability to distinguish different forms of nonliteral language. Participants listened to stories that ended in either a lie or an ironic joke. They were asked to decide the form of the nonliteral utterance and justify their responses. Almost none of the participants in any of the groups were able to correctly classify the ironic jokes, instead judging them to be lies because they did not correspond to reality. Their errors were similar to those made by younger normally developing children, but contrasted with those made by brain-damaged adults. These data are taken as further evidence that neurodevelopmental disorders are quite different from acquired brain disorders and require different neuropsychological models. The findings from this study also have important implications for considering the difficulties that adolescents with WS and other disorders will have in everyday social situations, especially among peers.
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PMID:Can adolescents with Williams syndrome tell the difference between lies and jokes? 1273 21

Despite increasing empirical data to the contrary, it continues to be claimed that mor-phosyntax and face processing skills of people with Williams syndrome are intact. This purported intactness, which coexists with mental retardation, is used to bolster claims about innately specified, independently functioning modules, as if the atypically developing brain were simply a normal brain with parts intact and parts impaired. Yet this is highly unlikely, given the dynamics of brain development and the fact that in a genetic microdeletion syndrome the brain is developing differently from the moment of conception, throughout embryogenesis, and during postnatal brain growth. In this article, we challenge the intactness assumptions, using evidence from a wide variety of studies of toddlers, children, and adults with Williams syndrome.
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PMID:Dethroning the myth: cognitive dissociations and innate modularity in Williams syndrome. 1273 26

Although much research has focused on the cognitive-linguistic profile associated with Williams syndrome, studies have yet to follow up on preliminary observations suggesting increased anxiety and fears in persons with this disorder. To this aim, Study 1 compared fears in 120 participants with Williams syndrome to 70 appropriately matched persons with mental retardation of mixed etiologies. Study 2 assessed differences in parent versus child reports of fears in 36 Williams syndrome and 24 comparison group parent-child dyads. In Study 3, rates of phobia and other anxiety disorders were assessed in standardized psychiatric interviews with the parents of 51 individuals with Williams syndrome. Relative to their counterparts, persons with Williams syndrome had significantly more fears as well as a wider range of frequently occurring fears, as reported by either parents or participants themselves. Children in both groups reported more fears than their parents. Whereas generalized and anticipatory anxiety were found in 51% to 60% of the sample with Williams syndrome, specific phobia was more prevalent, with 96% showing persistent and marked fears and 84% avoiding their fears or enduring them with distress. The feasibility of cognitive-behavioral treatments for phobia is discussed, as are implications for future research.
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PMID:Anxiety, fears, and phobias in persons with Williams syndrome. 1273 29

Williams syndrome is a rare congenital syndrome with distinctive craniofacial features, cardiovascular abnormalities, and behavior characteristics including mental retardation. The dental abnormalities have received scant attention in previous literature. The aim of this study was to describe dental characteristics in individuals with Williams syndrome. In a group of 41 individuals more than 10 years of age, 40.5% had agenesis of one or more permanent teeth and 11.9% had agenesis of 6 permanent teeth or more. The mesio-distal and labio-lingual dimensions of permanent tooth crowns were measured on 31 dental study casts from individuals older than 12 years. The mesio-distal and labio-lingual dimensions were significantly smaller compared with a reference sample. An analysis of tooth morphology was performed on the same dental study casts revealing altered tooth morphology. A high proportion of maxillary and mandibular incisors was tapered or screwdriver shaped. An evaluation of taurodontism on mandibular permanent molars was performed using a metric crown-body/root ratio. However, most of the molars rated as being taurodontic had short or extremely short total tooth lengths and could thus be rated taurodontic without meeting the classical definition. The results of this study indicate that although there is variation in dental development in individuals with Williams syndrome, agenesis of permanent teeth in combination with aberrations in tooth size and morphology may affect dental esthetics and complicate orthodontic and prosthodontic treatment.
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PMID:Dental characteristics in Williams syndrome: a clinical and radiographic evaluation. 1286 85


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