Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel interaction between GATA4 and TBX5 could explain phenotypic similarities (atrial septal defects) between patients with mutations in GATA4 or TBX5. The cardiac transcription factor GATA4 has not previously been implicated in a human disorder but a recent paper by Garg et al. provides evidence of mutations in GATA4 that cause atrial septal defects. Mutations in TBX5 have already been shown to cause similar atrial septal defects in Holt-Oram syndrome.
 ...
PMID:Interaction makes the heart grow stronger. 1455 51

Holt-Oram syndrome (HOS) is a multiple malformation syndrome associated with congenital heart malformation (CHM) and caused by mutations in the TBX5 transcription factor. Effective prenatal genetic diagnosis of HOS is limited by factors that modify clinical manifestations and confound prediction of an individual's phenotype. Although preimplantation genetic diagnosis (PGD) has been applied to complex disorders with some cardiovascular manifestations, its utility in Mendelian CHM has not been previously demonstrated. We tested whether PGD and in vitro fertilization (IVF) technology, including oocyte donation, can identify fertilized eggs affected by HOS for potential embryo selection. Five donor oocytes were fertilized in vitro with sperm from a HOS patient heterozygous for a Glu69ter-TBX5 mutation and then underwent embryo biopsy and genotyping. One carried the Glu69ter-TBX5 mutation; all others had wildtype genotypes. Two wildtype blastocysts were transferred to the mother, and the resulting singleton pregnancy was successfully delivered. Mutational analysis of fetal amniocytes and postpartum umbilical cord blood confirmed PGD. Fetal ultrasonography as well as postpartum electrocardiography and echocardiography also validated accurate prediction of normal skeletal and cardiac phenotypes. We conclude that PGD is an effective reproductive strategy for HOS patients. As more genetic etiologies for CHM are identified, application of PGD as adjunctive therapy to IVF will be increasingly available to prevent transmission of such diseases from affected parents to their children. Clinical application of PGD must balance the benefits of avoiding disease transmission with the medical risks and financial burdens of IVF.
 ...
PMID:Preimplantation genetic diagnosis of human congenital heart malformation and Holt-Oram syndrome. 1503 79

TBX5 is a member of the T-box gene family and encodes a transcription factor involved in cardiac and limb development. Mutations of TBX5 cause Holt-Oram syndrome (HOS), an autosomal-dominant condition with congenital cardiac defects and forelimb anomalies. Here, we used a GAL4-TBX5 fusion protein in a modified yeast-one hybrid system to elucidate the TBX5 transactivating domain. Using a series of deletion mutations of TBX5, we narrowed down its functional domain to amino acids 339-379 of its C-terminal half; point mutagenesis analysis then showed that the loss of amino acids 349-351 abolished transactivation. This result was confirmed in mammalian cells. Furthermore, wild-type TBX5, but not TBX5 with mutations at the amino acids 349-351, has ability to inhibit NCI-H1299 cell growth also suggesting that these amino acids are crucial for the TBX5 function in mammalian cells. In addition, to identify the nuclear localization signal of TBX5, we searched for cluster of basic amino acids. We found that the deletion of the KRK sequence at amino acids 325-327 mislocalizes TBX5 to cytoplasm, suggesting that these amino acids serve as a nuclear localization signal. These studies enhance our understanding of the structure-function relationship of TBX5 and suggest that truncation mutations of TBX5 could cause HOS through the loss of its transactivating domain and/or the nuclear localization signal.
 ...
PMID:Identification of the TBX5 transactivating domain and the nuclear localization signal. 1508 19

TBX5 is a member of the T-box gene family and encodes a transcription factor that regulates the expression of other gene(s) in the developing heart and limbs. Mutations of TBX5 cause Holt-Oram syndrome (HOS), an autosomal dominant condition characterized by congenital heart defects and limb anomalies. How TBX5 gene expression is regulated is still largely unknown. In order to identify transcription factors regulating TBX5 expression, we examined the 5'-flanking region of the human TBX5 gene. We determined that up to 300 bp of the 5'-flanking region of the TBX5 gene was necessary for promoter activity in mouse cardiomyocyte ECL2 cells. One GC box, three potential T-box-like binding elements (TBE-A, -B, and -C), and one NKX2.5 binding site were identified. Site-directed mutagenesis of the potential binding sites revealed that the GC box, TBE-B, TBE-C, and NKX2.5 are functionally positive for the expression of TBX5. DNA footprint analysis showed that these binding regions are resistant to DNaseI digestion. Electrophoretic mobility shift assays (EMSAs) further demonstrated the protein-DNA interactions at the GC box and the potential TBE-B, TBE-C, and NKX2.5 sites in a sequence-specific manner. The ability of TBX5 to regulate its own promoter was demonstrated by the ability of ectopically expressed human TBX5 to increase reporter expression. We conclude that the GC box, T-box-like binding elements, and NKX2.5 binding site play important roles in the regulation of TBX5 expression, and that TBX5 is likely to be autoregulated as part of the mechanism of its transcription.
 ...
PMID:TBX5, a gene mutated in Holt-Oram syndrome, is regulated through a GC box and T-box binding elements (TBEs). 1509 14

The T-box transcription factor Tbx5 is important in mammalian cardiac development. Mutations in the human TBX5 gene cause Holt-Oram syndrome (HOS), a disorder characterized by heart and upper limb deformities. To determine the role of TBX5 in non-HOS patients with complex cardiac malformations, we analyzed 68 explanted hearts from unrelated patients with various cardiac abnormalities including atrial (ASD), ventricular (VSD) and atrioventricular septal defects (AVSD). Direct sequencing detected nine mutations in diseased cardiac tissues of patients, eight of which are novel. Six mutations would affect amino acids in the T-domain, and one (c.236C>T, p.Ala79Val) is within the recently identified nuclear localization signal (NLS1) region. Further, mutations were found in patients with ASD and AVSD, but not with VSD; and mutations were absent in normal heart tissue of same patients, thus indicating somatic origin. Our results suggest a possible role of somatically occurring TBX5 mutations in congenital heart disease. We show for the first time TBX5 mutations in non-HOS associated cardiac malformations and we identified a novel missense mutation that would impact nuclear localization of TBX5.
 ...
PMID:TBX5 mutations in non-Holt-Oram syndrome (HOS) malformed hearts. 1522 98

Atrial septal defect is one of the most common forms of congenital heart malformation. We identified a new locus linked with atrial septal defect on chromosome 14q12 in a large family with dominantly inherited atrial septal defect. The underlying mutation is a missense substitution, I820N, in alpha-myosin heavy chain (MYH6), a structural protein expressed at high levels in the developing atria, which affects the binding of the heavy chain to its regulatory light chain. The cardiac transcription factor TBX5 strongly regulates expression of MYH6, but mutant forms of TBX5, which cause Holt-Oram syndrome, do not. Morpholino knock-down of expression of the chick MYH6 homolog eliminates the formation of the atrial septum without overtly affecting atrial chamber formation. These data provide evidence for a link between a transcription factor, a structural protein and congenital heart disease.
 ...
PMID:Mutation in myosin heavy chain 6 causes atrial septal defect. 1573 45

Holt-Oram syndrome, the major "heart-hand" syndrome is defined by the association of radial defects or triphalangeal thumbs and septal heart defects. The transmission is autosomal dominant and the causative gene has been shown to be TBX5, located on 12q24.1, which encodes a transcription factor. Genetic heterogeneity has been suggested by several reports. We identified a 14(q23.3 approximately 24.2q31.1) deletion in a boy presenting severe bilateral asymmetrical radial aplasia, congenital heart defects, and developmental delay. This deletion, whose size could be estimated to be 9.6-13.7 Mb, was shown to be inherited via his mother's interchromosomal insertion. This is the second report of a chromosome 14 interstitial deletion associated with clinical features of Holt-Oram syndrome. These observations suggest the existence of a new "heart-hand" locus on chromosome 14q.
 ...
PMID:Molecular characterization of a 14q deletion in a boy with features of Holt-Oram syndrome. 1581 3

Germline mutations of the TBX5 gene were identified as the primary cause in up to 70% of patients with Holt-Oram syndrome (HOS), an autosomal dominant disorder characterized by malformations of the upper limbs and cardiac defects. Furthermore, somatic mutations of the TBX5 gene have been described in diseased heart tissues of patients with congenital heart defects of different cause. The relationship between genotype and phenotype remains unclear and the underlying mechanism of the pathogenic effect is not solved. In this report, we introduce the 'TBX5 Gene Mutation Database,' an online locus specific database containing germline and somatic mutations of the TBX5 gene. The permanently updated data collection includes all reported mutations beginning with the first description of the gene in 1997. With our database we complement the existing resources by: 1) giving a complete review of the so far reported mutation spectrum in TBX5 considering the clinical relevance; 2) linkage of the mutational data to the corresponding gene location and PubMed-Abstracts; and 3) additional links to other related resources like SNP database, sequences and literature references. The usage of our database will help to quickly find informations about genetic variations within the TBX5 gene. Here we describe the database structure, content, and potential applications (http://www.uni-leipzig.de/~genetik/TBX5).
 ...
PMID:The human TBX5 gene mutation database. 1613 40

Holt-Oram syndrome (HOS) is an autosomal dominant heart-hand syndrome characterized by congenital heart disease (CHD) and upper limb deformity, and caused by mutations in the TBX5 gene. To date, the sensitivity of TBX5 genetic testing for HOS has been unclear. We now report mutational analyses of a nongenetically selected population of 54 unrelated individuals who were consecutively referred to our center with a clinical diagnosis of HOS. TBX5 mutational analyses were performed in all individuals, and clinical histories and findings were reviewed for each patient without reference to the genotypes. Twenty-six percent of the complete cohort was shown to have mutations of the TBX5 gene. However, among those subjects for whom clinical review demonstrated that their presentations met strict diagnostic criteria for HOS, TBX5 mutations were identified in 74%. No mutations were identified in those subjects who did not meet these criteria. Thus, these studies validate our clinical diagnostic criteria for HOS including an absolute requirement for preaxial radial ray upper limb malformation. Accordingly, TBX5 genotyping has high sensitivity and specificity for HOS if stringent diagnostic criteria are used in assigning the clinical diagnosis.
 ...
PMID:TBX5 genetic testing validates strict clinical criteria for Holt-Oram syndrome. 1618 9

The T-box transcription factor TBX5 plays essential roles in cardiac and limb development. Various mutations in the TBX5 gene have been identified in patients with Holt-Oram syndrome, which is characterized by congenital defects in the heart and upper extremities. In this study, we identified a WW-domain-containing transcriptional regulator TAZ as a potent TBX5 coactivator. TAZ directly associates with TBX5 and markedly stimulates TBX5-dependent promoters by interacting with the histone acetyltransferases p300 and PCAF. YAP, a TAZ-related protein with conserved functional domains, also stimulates TBX5-dependent transcription, possibly by forming a heterodimer with TAZ. TBX5 lacks a PY motif, which mediates the association of other proteins with TAZ, and interacts with TAZ through multiple domains including its carboxyl-terminal structure. Truncation mutants of TBX5 identified in patients with Holt-Oram syndrome were markedly impaired in their ability to associate with and be stimulated by TAZ. These findings reveal key roles for TAZ and YAP in the control of TBX5-dependent transcription and suggest the involvement of these coactivators in cardiac and limb development.
 ...
PMID:A WW domain protein TAZ is a critical coactivator for TBX5, a transcription factor implicated in Holt-Oram syndrome. 1633 60


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>