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Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on a case of a 60-year-old man with progressive heart failure, mitral and aortic valve insufficiency and bilateral asymmetrical skeletal upper-limb deformities. Central to the suspicion of Holt-Oram syndrome in this patient was the surgical finding of agenesis of the left pericardium. A Holt-Oram syndrome diagnostic was confirmed through molecular analysis of the TBX5 gene. A new amino acid substitution at position 61 of the TBX5 gene was identified and confirmed the clinical diagnosis of Holt-Oram syndrome. The clinical presentation of the present case broadens the clinical spectrum of Holt-Oram syndrome and point out the importance of Tbx 5 in pericardium development. It is still an unstudied issue whether TBX5 mutations may also be present in other clinical presentations where absence of the pericardium is a feature.
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PMID:Holt-Oram syndrome presenting as agenesis of the left pericardium. 1637 38

Okihiro syndrome (OS) is defined by forelimb defects associated with the eye disorder Duane anomaly and results from mutations in the gene SALL4. Forelimb defects in individuals with OS range from subtle thumb abnormalities to truncated limbs. Mutations in the T-box transcription factor TBX5 cause Holt-Oram syndrome (HOS), which results in forelimb and heart defects. Although mutations in TBX5 result in HOS, it has been predicted that these mutations account for only approximately 30% of all individuals with HOS. Individuals with OS and HOS limb defects are very similar, in fact, individuals with mutations in SALL4 have in some cases previously been diagnosed with HOS. Using zebrafish as a model, we have investigated the function of sall4 and the relationship between sall4 and tbx5, during forelimb development. We demonstrate that sall4 and a related gene sall1 act downstream of tbx5 and are required for pectoral fin development. Our studies of Sall gene family redundancy and tbx5 offer explanations for the similarity of individuals with OS and HOS limb defects.
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PMID:sall4 acts downstream of tbx5 and is required for pectoral fin outgrowth. 1650 Nov 70

TBX5 mutations cause the cardiac and limb defects of the autosomal dominant Holt-Oram syndrome (HOS). We have explored the role of the TBX5 transcription factor during cardiogenesis and have elucidated some of its functions in regulating myocardial cell proliferation and proepicardial cell migration. Our identification of TBX5 mutations has enabled us to offer genetic testing for diagnosis of HOS in patients and also to perform preimplantation genetic diagnosis on blastocysts for couples desiring to have a child unaffected by HOS. We hope that our genetic testing approach will serve as a paradigm for mutation screening in other inherited syndromes.
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PMID:Using the TBX5 transcription factor to grow and sculpt the heart. 1669 75

Dominant mutations in the T-box transcription factor gene TBX5 cause Holt-Oram syndrome (HOS), an inherited human disease characterized by upper limb malformations and congenital heart defects (CHDs) of variable severity. We hypothesize that minor alterations in the dosage of Tbx5 directly influences severity of CHDs. Using a mouse allelic series, we show a sensitive inverse correlation between Tbx5 dosage and abnormal cardiac morphogenesis and gene expression. The CHDs found in mice harbouring a hypomorphic allele of Tbx5 (Tbx5(lox/+) mice) are less pronounced than those found in Tbx5 haploinsufficient mice (Tbx5(del/+)), and homozygous hypomorphic (Tbx5(lox/lox)) embryos have noticeably more advanced cardiac development than Tbx5 null (Tbx5(del/del)) embryos. Examination of target gene expression across the allelic series uncovers very fine sensitivity across the range of Tbx5 dosages, in which some genes respond dramatically differently to only 15% differences in Tbx5 mRNA levels. This analysis was expanded to a genome-wide level, which uncovered a Tbx5 dosage-sensitive genetic program involving a network of cardiac transcription factors, developmentally important cell-cell signaling molecules, and ion channel proteins. These results indicate an exquisite sensitivity of the developing heart to Tbx5 dosage and provide significant insight into the transcriptional and cellular mechanisms that are disrupted in CHDs.
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PMID:Tbx5-dependent rheostatic control of cardiac gene expression and morphogenesis. 1687 Jan 72

Mutations in the gene TBX5 cause Holt-Oram syndrome (HOS), an autosomal dominant disorder characterized by anterior (i.e., radial ray) upper limb malformations and congenital heart defects and/or cardiac conduction anomalies. The detection rate for TBX5 mutations in HOS patients has been given as 30-35% in most reports. However, a detection rate of 74% was reported when strict clinical inclusion criteria for HOS were applied prior to TBX5 analysis. Still, in a significant proportion of typical HOS cases no mutation can be found within the TBX5 coding region and flanking intronic sequences. One explanation could be that large but submicroscopic deletions of TBX5 could cause HOS, yet only one such TBX5 deletion has been reported to date. We developed a quantitative Real Time PCR strategy to detect large, submicroscopic deletions in TBX5. Using this assay, we screened a total of 102 TBX5 mutation negative patients and discovered two novel intragenic deletions. One deletion of 7756 bp removes exon 6 and a considerable part of the neighboring intronic sequences, and the other of 3695 bp removes exon 9 with the stop codon and the 3'UTR completely as well as a part of the preceding intron 8. We conclude that quantitative Real Time PCR is a reliable method to detect submicroscopic deletions within TBX5. However, such deletions explain only approximately 2% of the TBX5 mutational spectrum in HOS cases. In addition, we also present eight novel TBX5 mutations (three nonsense, one splice mutation, four short deletions) as detected by direct sequencing in 21 families not previously analyzed for mutations.
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PMID:Expanding the spectrum of TBX5 mutations in Holt-Oram syndrome: detection of two intragenic deletions by quantitative real time PCR, and report of eight novel point mutations. 1691 9

Tbx5 is essential for initiation of the forelimb, and its deletion in mice results in the failure of forelimb formation. Misexpression of dominant-negative forms of Tbx5 results in limb truncations, suggesting Tbx5 is also required for forelimb outgrowth. Here we show that Tbx5 is expressed throughout the limb mesenchyme in progenitors of cartilage, tendon and muscle. Using a tamoxifeninducible Cre transgenic line, we map the time frame during which Tbx5 is required for limb development. We show that deletion of Tbx5 subsequent to limb initiation does not impair limb outgrowth. Furthermore, we distinguish two distinct phases of limb development: a Tbx5-dependent limb initiation phase, followed by a Tbx5-independent limb outgrowth phase. In humans, mutations in the T-box transcription factor TBX5 are associated with the dominant disorder Holt-Oram syndrome (HOS), which is characterised by malformations in the forelimb and heart. Our results demonstrate a short temporal requirement for Tbx5 during early limb development, and suggest that the defects found in HOS arise as a result of disrupted TBX5 function during this narrow time window.
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PMID:Tbx5 is dispensable for forelimb outgrowth. 1713 67

The Holt-Oram syndrome or atriodigital dysplasia is an autosomal dominant disorder with near complete penetrance and variable expression, caused by mutations of the TBX5 gene (12q24.1), affecting one in 100 000 live births. 60% of cases are familial and 40% sporadic. We present the case of a 24 years old male patient with a personal history of bilateral coxa vara surgically corrected on the right at the age of 8 years, complicated by osteochondritis, short stature (160 cm), underweight (37 kg, BMI 14.45 kg/cm(2)), triangular face, micrognathia, down slanting palpebral fissures, hypertelorism, low set ears, scoliosis, narrow shoulders, shortened left arm, left thumb agenesia, limited supination, abnormal toes, hypoplastic muscles, atrial septal defect ostium secundum type, incomplete right bundle branch block, hypoacusia and normal intelligence.
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PMID:Holt-Oram syndrome. 1750 54

Holt-Oram syndrome (MIM #142900) is an autosomal-dominant disorder characterized by radial ray deformities of the upper limb associated with cardiac septation and/or conduction defects. The disorder is caused by mutations in the transcription factor TBX5. Several studies report a rather low detection rate (range, 22-35%) of TBX5 mutations in patients with a clinical suspicion of Holt-Oram syndrome. The low detection rate is attributed to clinical misdiagnosis and genetic heterogeneity. However, a detection rate up to 74% has been reported when strict inclusion criteria for Holt-Oram syndrome are applied before genetic testing. We performed mutational analysis in a cohort of 27 unrelated patients referred with a clinical diagnosis of Holt-Oram syndrome. Seven TBX5 mutations were detected by direct sequencing. The detection rate of TBX5 mutations in this co hort of patients was 25.9% but increased to 54% when the strict phenotypical criteria were applied. No mutations were found in patients who did not meet these strict phenotypical criteria. Interestingly, we were unable to identify a TBX5 mutation in six of 13 patients who did meet the strict criteria. This study confirms TBX5 genetic testing should be reserved for patients who fulfill the strict phenotypic criteria for Holt-Oram syndrome.
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PMID:Novel TBX5 mutations in patients with Holt-Oram syndrome. 1753 87

Holt-Oram syndrome (HOS) (OMIM 142900) is characterized by upper-extremity malformations involving the radial, thenar, or carpal bones and a personal and/or family history of congenital heart defects (CHDs). It is inherited in an autosomal dominant manner. The TBX5 gene located on chromosome 12 (12q24.1) is the only gene currently known to be associated with HOS and is associated with variable phenotypes. We report on the clinical and molecular characterization of a HOS family with three affected individuals and a novel mutation (Lys88ter). We discuss genotype-phenotype correlations, the presence of foot anomalies in one affected individual, and the role of atypical features in HOS differential diagnosis.
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PMID:Holt-Oram syndrome associated with anomalies of the feet. 1835 27

We present a rare case of familial Holt-Oram syndrome diagnosed sonographically at 18 weeks of gestation. The foetus had serious bilateral upper limb malformations, a ventricular septal defect and a type B interrupted aortic arch, while the mother had bilateral upper limb malformations only. The pregnancy was terminated. A pathological and radiological examination of the foetus confirmed the prenatal sonographic findings. Although genetic investigation of TBX5 mutations was not available in our locality at the time of diagnosis, the geneticists made a clinical diagnosis of familial Holt-Oram syndrome. The clinical features of our case completely fulfilled the strict diagnostic criteria for the syndrome. The cardiac malformations most commonly associated with Holt-Oram syndrome are atrial or ventricular septal defects. To the best of our knowledge, a prenatal diagnosis of Holt-Oram syndrome in association with a type B interrupted aortic arch has not been reported in the English literature before.
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PMID:Prenatal sonographic diagnosis of familial Holt-Oram syndrome associated with type B interrupted aortic arch. 1868 67


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