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

Much existing research on Williams syndrome (WS) has focused on the individuals' unusual cognitive profile, with less emphasis placed on the developmental and neural underpinnings of the disorder. We review recent findings from brain imaging and begin to discuss links from these data to the behavioral phenotype. Overall brain size is significantly reduced in individuals with WS, as it is in many mental retardation syndromes. However, the specific profile of deficits in WS, particularly the visuospatial deficits, appears to be linked to parietal lobe abnormalities. Results from both genetic and brain imaging studies have provided useful insights into WS neurobiology. However, future work needs to remediate the lack of studies investigating developmental processes.
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PMID:Neurodevelopmental and behavioral issues in Williams syndrome. 1738 29

Williams-Beuren syndrome (WS) is a rare multi-system genomic disorder, caused by 7q11.23 microdeletion with a prevalence of 1/7500-1/20,000 live births. Clinical phenotype includes typical facial dysmorphism (elfin face), mental retardation associated with a peculiar neuropsychological profile and congenital heart defects. We investigated 22 WS patients (mean age of 9.7 years, range 1 day to 39 years) with a multi-specialist follow-up protocol comprehensive of neuropsychological, cardiologic, nephrologic, ophthalmologic, endocrinologic, gastroenterologic, odontostomatologic and orthopaedic evaluations. The mean age at diagnosis was 5.38 years, being 1.02 years when genetic evaluation was requested for congenital heart defects (CHD) and 10.68 years in case of mental retardation and/or abnormal neuropsychological profile without an evident CHD. All patients showed facial dysmorphisms, with supravalvular aortic stenosis (SVAS) as the most common cardiovascular anomaly (12/22), followed by peripheral pulmonary stenosis (9/22); interestingly, in one patient we detected a total anomalous pulmonary venous return (TAPVR), confirming the possible association of this rare CHD with WS. Hypertension was detected by 24-h ambulatory blood pressure monitoring in 7/22 cases. A cognitive assessment was performed in 13 patients older than 6 years, showing various degrees of mental retardation in 12 and a normal intelligence quotient (IQ) in a single patient; evaluation of developmental milestones revealed various grades of developmental delay in all the patients younger than 6 years. Chiari malformation type 1 was found in 3 patients. Our study underlines a remarkable diagnostic delay in patients who present to genetic evaluation because of mental retardation and/or peculiar neuropsychological profile lacking an evident cardiopathy and confirms the multi-systemic nature of WS leading to a high clinical presentation's variability and complex follow-up strategies.
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PMID:Presenting phenotype and clinical evaluation in a cohort of 22 Williams-Beuren syndrome patients. 1762 98

The Williams-Beuren syndrome is the association of elf-like facies, mental retardation with cardiovascular anomalies, the most common of which is supravalvular aortic stenosis. This lesion may be focal or associated with hypoplasia of the distal aorta. The treatment is surgical and the role of interventional cardiological treatment is poorly defined. The authors report the case of a child with typical Williams-Beuren syndrome. An initial, very localised surgical aortic repair was performed at 3 months of age for a discrete supravalvular aortic stenosis. Two months later, a second operation was required for a new stenosis of the distal anastomosis associated with marked hypoplasia of the aortic arch. The progressive constitution of an isthmic coarctation led to the percutaneous implantation of a stent followed by two balloon dilatations. Only the first two endoluminal procedures successfully reduced the transisthmic pressure gradient. An antihypertensive treatment was given and regular echocardiography allows monitoring of the adaptation of the left ventricle.
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PMID:[The Williams-Beuren syndrome: reconstruction of the thoracic aorta combining surgery and endovascular treatment]. 1764 76

The purpose of this study was to determine which tests of effort and motivation would be appropriate for use with patients with mental retardation when feigning of cognitive deficits is suspected. The seven measures evaluated included the WMS-III Rarely Missed Index Test, forced-choice recognition portion of the California Verbal Learning Test-II, Reliable Digit Span test, Rey 15-Item Test, Rey Dot Counting Test, the Rey 15-Item Test with Recognition Trial, and the Vocabulary (V)-Digit Span (DS) difference score. Results indicated that the forced-choice portion of the CVLT-II, the V-DS difference score, and the Rarely Missed Index Test from the WMS-III might be appropriate for use with this population with passing rates of 89%, 98%, and 91% respectively.
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PMID:The performance of individuals with mental retardation on cognitive tests assessing effort and motivation. 1767 47

A 28-month-old boy (height, 76 cm; weight, 9.4 kg) diagnosed as having Williams syndrome presented for dental care. We report a case of postoperatively suspected malignant hyperthermia after the administration of general anesthesia for dental treatment in this patient with severe supravalvular aortic stenosis and pulmonary artery hypoplasia. Anesthesia was maintained through the inhalation of nitrous oxide and sevoflurane with oxygen. The patient was hemodynamically stable and no other abnormalities were observed. After the completion of the dental treatment, he was transferred to the pediatric ward. On arrival at the ward, the patient's core temperature increased to 39.5 degrees C and tachypnea (RR, 30 breaths/min) was observed. The SPO2 during inhalation was slightly low (92%-93%). Serum biochemistry revealed an elevated CK level (1345 U/L) but no other abnormal findings. Twelve hours after the dental treatment, the patient's core temperature fell to 37.4 degrees C. After hospitalization for 4 days, the patient was discharged in good condition. In the present case, general anesthesia was employed for dental treatment despite severe supravalvular aortic stenosis and peripheral pulmonary artery hypoplasia, because conventional dental therapy was very difficult as a result of the patient's mental retardation and hyperkinesia. The present case suggests that the use of volatile agents that could trigger malignant hyperthermia should be avoided wherever possible.
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PMID:General anesthesia for dental treatment in a Williams syndrome patient with severe aortic and pulmonary valve stenosis: suspected episode of postoperatively malignant hyperthermia. 1768 62

Williams syndrome is a rare congenital disorder involving the cardiovascular system, mental retardation, distinctive facial features, and tooth anomalies. It is caused by the heterozygous deletion of approximately 1.6 Mb encompassing 28 genes on human chromosome 7q11.23. It has been suggested that the genes responsible for craniofacial anomalies are located in the telomeric end region, which harbors three members of the TFII-I gene family (Tassabehji et al. [2005] Science 310:1184). To recognize potential candidate genes for the tooth anomalies in Williams syndrome, we carried out comparative in situ hybridization analysis of members of TFII-I gene family during murine odontogenesis. Gtf2i showed widespread expression in the developing head but was higher in the developing teeth than surrounding tissues throughout tooth development. At the bud stage, Gtf2ird1 and Gtf2ird2 were expressed in the epithelial buds. At the early bell stage, expression of Gtf2ird1 and Gtf2ird2 was observed in preameloblasts and preodontoblasts.
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PMID:TFII-I gene family during tooth development: candidate genes for tooth anomalies in Williams syndrome. 1782 43

Studies of age-related features of cognitive-behavioral deficits produced by genetic mutations permit us to draw inferences about how brain development may be related cognitive ability as the child ages. Except for Down syndrome (DS) and the fragile X mutation (FRAXA), little is known about the longitudinal changes in cognitive-behavioral development in individuals with genetic abnormalities producing learning disabilities (LD) or mental retardation (MR). The purpose of this prospective study was to compare and contrast age related to cognitive abilities, adaptive and maladaptive behaviors in children and adolescents in the same age range, diagnosed with one of three genetic disorders: the FRAXA mutation, Neurofibromatosis type 1 (NF1) or Williams-Beuren syndrome (WBS). We also sought to examine whether cognitive-behavioral abilities associated with these three genetic disorders were related systematically to age. We examined 108 children, ages 4-15 years, with FRAXA, WBS, or NF1. Results show that there is a significant negative correlation between age and IQ, and between age and adaptive behavior (DQ) scores, in children with FRAXA and WBS, but not in children with NF1. All three groups of children have unusually high proportions of maladaptive behavior, ranging from 1/6 children with NF1 to 2/3 children with FRAXA. Cognitive and adaptive behavior profiles of children with FRAXA and WBS were also surprisingly similar. Our findings suggest the need for examining longitudinal developmental cognitive-behavioral changes in children and adolescents with all genetic disorders that produce LD or MR.
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PMID:Studies of age-correlated features of cognitive-behavioral development in children and adolescents with genetic disorders. 1785 66

Williams syndrome (WS) is a rare genetically based neurodevelopmental disorder which is associated with mental retardation and a distinctive cognitive and behavioural profile, including weaknesses in visuospatial processing but preserved language abilities and face recognition. Relative to the cognitive characteristics of WS, there is a dearth of research into the movement problems associated with this syndrome. This is despite the evidence from clinical and experimental studies that indicate disordered movement may be an important neuromotor characteristic of WS. This article reviews the current neuroanatomical and behavioural literature on visuomotor deficits in WS, and examines the differential role of fronto-parietal and cerebellar regions in motor dysfunction. The role of these brain regions in disturbances of visuomotor control is discussed in the context of the important interaction with attention, executive and planning deficits in WS. Finally, directions are provided for future research emphasising the need to examine developmental changes in motor functioning across a range of movement parameters and to investigate the functional correlates of abnormal neural connectivity in WS. It is concluded that further investigation of motor dysfunction in WS may provide us with a greater understanding of how important movement-related brain regions develop and operate.
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PMID:Fronto-parietal and cerebellar contributions to motor dysfunction in Williams syndrome: a review and future directions. 1800 60

Fluorescent in situ hybridisation (FISH) is a complementary cytogenetic method which has an important role in discovering unsolved cases of mental retardation and multiple anomalies. The ability of this method to detect complex and cryptic chromosomal rearrangements exceeds the resolution of the usual cytogenetic banding techniques; therefore it has a wide implementation in modern cytogenetic laboratories - in routine work, as well as for research purposes. We analysed 19 patients with microdeletion syndromes - 9 patients with Williams syndrome, 4 patients with Prader-Willi syndrome, and 6 patients with DiGeorge syndrome. On the basis of evaluation of facial dysmorphism and the presence of specific major anomalies, all the patients met the criteria for the diagnosis of the syndrome. FISH studies were performed, confirming the suspected syndrome in patients.
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PMID:Implementation of Fluorescent in situ hybridization (FISH) as a method for detecting microdeletion syndromes - our first experiences. 1835 81

Studies have reported that a selective deficit in visual motion processing is present in certain developmental disorders, including Williams syndrome and autism. More recent evidence suggests a visual motion impairment is also present in adults with fragile X syndrome (FXS), the most common form of inherited mental retardation. The goal of the current study was to examine low-level cortical visual processing in infants diagnosed with FXS in order to explore the developmental origin of this putative deficit. We measured contrast detection of first-order (luminance-defined) and second-order (contrast-defined) gratings at two levels of temporal frequency, 0 Hz (static) and 4 Hz (moving). Results indicate that infants with FXS display significantly higher detection thresholds only for the second-order, moving stimuli compared to mental age-matched typically developing controls.
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PMID:Contrast detection in infants with fragile X syndrome. 1845 56


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