Talk:Williams Syndrome: Difference between revisions

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===Genome rearrangements detected by SNP microarrays in individuals with intellectual disability referred with possible Williams syndrome===
PLoS One. 2010 Aug 31;5(8):e12349.
Pani AM, Hobart HH, Morris CA, Mervis CB, Bray-Ward P, Kimberley KW, Rios CM, Clark RC, Gulbronson MD, Gowans GC, Gregg RG.
Source
Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America.
Abstract
BACKGROUND:
Intellectual disability (ID) affects 2-3% of the population and may occur with or without multiple congenital anomalies (MCA) or other medical conditions. Established genetic syndromes and visible chromosome abnormalities account for a substantial percentage of ID diagnoses, although for approximately 50% the molecular etiology is unknown. Individuals with features suggestive of various syndromes but lacking their associated genetic anomalies pose a formidable clinical challenge. With the advent of microarray techniques, submicroscopic genome alterations not associated with known syndromes are emerging as a significant cause of ID and MCA.
METHODOLOGY/PRINCIPAL FINDINGS:
High-density SNP microarrays were used to determine genome wide copy number in 42 individuals: 7 with confirmed alterations in the WS region but atypical clinical phenotypes, 31 with ID and/or MCA, and 4 controls. One individual from the first group had the most telomeric gene in the WS critical region deleted along with 2 Mb of flanking sequence. A second person had the classic WS deletion and a rearrangement on chromosome 5p within the Cri du Chat syndrome (OMIM:123450) region. Six individuals from the ID/MCA group had large rearrangements (3 deletions, 3 duplications), one of whom had a large inversion associated with a deletion that was not detected by the SNP arrays.
CONCLUSIONS/SIGNIFICANCE:
Combining SNP microarray analyses and qPCR allowed us to clone and sequence 21 deletion breakpoints in individuals with atypical deletions in the WS region and/or ID or MCA. Comparison of these breakpoints to databases of genomic variation revealed that 52% occurred in regions harboring structural variants in the general population. For two probands the genomic alterations were flanked by segmental duplications, which frequently mediate recurrent genome rearrangements; these may represent new genomic disorders. While SNP arrays and related technologies can identify potentially pathogenic deletions and duplications, obtaining sequence information from the breakpoints frequently provides additional information.
PMID: 20824207

Revision as of 12:29, 8 July 2011

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Cite this page: Hill, M.A. (2024, March 29) Embryology Williams Syndrome. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Williams_Syndrome

2011

Using novel control groups to dissect the amygdala's role in Williams Syndrome

Dev Cogn Neurosci. 2011 Jul;1(3):295-304.

Thornton-Wells TA, Avery SN, Blackford JU. Source Center for Human Genetics Research, Vanderbilt University Medical Center, 519 Light Hall, Nashville, TN 37232.

Abstract

Williams syndrome is a neurodevelopmental disorder with an intriguing behavioral phenotype-hypersociability combined with significant non-social fears. Previous studies have demonstrated abnormalities in amygdala function in individuals with Williams syndrome compared to typically-developing controls. However, it remains unclear whether the findings are related to the atypical neurodevelopment of Williams syndrome, or are also associated with behavioral traits at the extreme end of a normal continuum. We used functional magnetic resonance imaging (fMRI) to compare amygdala blood-oxygenation-level-dependent (BOLD) responses to non-social and social images in individuals with Williams syndrome compared to either individuals with inhibited temperament (high non-social fear) or individuals with uninhibited temperament (high sociability). Individuals with Williams syndrome had larger amygdala BOLD responses when viewing the non-social fear images than the inhibited temperament control group. In contrast, when viewing both fear and neutral social images, individuals with Williams syndrome did not show smaller amygdala BOLD responses relative to the uninhibited temperament control group, but instead had amygdala responses proportionate to their sociability. These results suggest heightened amygdala response to non-social fear images is characteristic of WS, whereas, variability in amygdala response to social fear images is proportionate to, and might be explained by, levels of trait sociability.

PMID: 21731599 http://www.ncbi.nlm.nih.gov/pubmed/21731599

2010

Negative autoregulation of GTF2IRD1 in Williams-Beuren syndrome via a novel DNA binding mechanism

J Biol Chem. 2010 Feb 12;285(7):4715-24. Epub 2009 Dec 9.

Palmer SJ, Santucci N, Widagdo J, Bontempo SJ, Taylor KM, Tay ES, Hook J, Lemckert F, Gunning PW, Hardeman EC. Source Department of Anatomy, School of Medical Sciences, The University of New South Wales, Sydney 2052, Australia. s.palmer@unsw.edu.au

Abstract

The GTF2IRD1 gene is of principal interest to the study of Williams-Beuren syndrome (WBS). This neurodevelopmental disorder results from the hemizygous deletion of a region of chromosome 7q11.23 containing 28 genes including GTF2IRD1. WBS is thought to be caused by haploinsufficiency of certain dosage-sensitive genes within the deleted region, and the feature of supravalvular aortic stenosis (SVAS) has been attributed to reduced elastin caused by deletion of ELN. Human genetic mapping data have implicated two related genes GTF2IRD1 and GTF2I in the cause of some the key features of WBS, including craniofacial dysmorphology, hypersociability, and visuospatial deficits. Mice with mutations of the Gtf2ird1 allele show evidence of craniofacial abnormalities and behavioral changes. Here we show the existence of a negative autoregulatory mechanism that controls the level of GTF2IRD1 transcription via direct binding of the GTF2IRD1 protein to a highly conserved region of the GTF2IRD1 promoter containing an array of three binding sites. The affinity for this protein-DNA interaction is critically dependent upon multiple interactions between separate domains of the protein and at least two of the DNA binding sites. This autoregulatory mechanism leads to dosage compensation of GTF2IRD1 transcription in WBS patients. The GTF2IRD1 promoter represents the first established in vivo gene target of the GTF2IRD1 protein, and we use it to model its DNA interaction capabilities.

PMID: 20007321 http://www.ncbi.nlm.nih.gov/pubmed/20007321

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2836076

http://www.jbc.org/content/285/7/4715.long


Genome rearrangements detected by SNP microarrays in individuals with intellectual disability referred with possible Williams syndrome

PLoS One. 2010 Aug 31;5(8):e12349.

Pani AM, Hobart HH, Morris CA, Mervis CB, Bray-Ward P, Kimberley KW, Rios CM, Clark RC, Gulbronson MD, Gowans GC, Gregg RG. Source Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America.

Abstract

BACKGROUND: Intellectual disability (ID) affects 2-3% of the population and may occur with or without multiple congenital anomalies (MCA) or other medical conditions. Established genetic syndromes and visible chromosome abnormalities account for a substantial percentage of ID diagnoses, although for approximately 50% the molecular etiology is unknown. Individuals with features suggestive of various syndromes but lacking their associated genetic anomalies pose a formidable clinical challenge. With the advent of microarray techniques, submicroscopic genome alterations not associated with known syndromes are emerging as a significant cause of ID and MCA.

METHODOLOGY/PRINCIPAL FINDINGS: High-density SNP microarrays were used to determine genome wide copy number in 42 individuals: 7 with confirmed alterations in the WS region but atypical clinical phenotypes, 31 with ID and/or MCA, and 4 controls. One individual from the first group had the most telomeric gene in the WS critical region deleted along with 2 Mb of flanking sequence. A second person had the classic WS deletion and a rearrangement on chromosome 5p within the Cri du Chat syndrome (OMIM:123450) region. Six individuals from the ID/MCA group had large rearrangements (3 deletions, 3 duplications), one of whom had a large inversion associated with a deletion that was not detected by the SNP arrays.

CONCLUSIONS/SIGNIFICANCE: Combining SNP microarray analyses and qPCR allowed us to clone and sequence 21 deletion breakpoints in individuals with atypical deletions in the WS region and/or ID or MCA. Comparison of these breakpoints to databases of genomic variation revealed that 52% occurred in regions harboring structural variants in the general population. For two probands the genomic alterations were flanked by segmental duplications, which frequently mediate recurrent genome rearrangements; these may represent new genomic disorders. While SNP arrays and related technologies can identify potentially pathogenic deletions and duplications, obtaining sequence information from the breakpoints frequently provides additional information.

PMID: 20824207