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Boussion S, Escande F, Jourdain AS, Smol T, Brunelle P, Duhamel C, Alembik Y, Attié-Bitach T, Baujat G, Bazin A, Bonnière M, Carassou P, Carles D, Devisme L, Goizet C, Goldenberg A, Grotto S, Guichet A, Jouk PS, Loeuillet L, Mechler C, Michot C, Pelluard F, Putoux A, Whalen S, Ghoumid J, Manouvrier-Hanu S, Petit F. TAR syndrome: Clinical and molecular characterization of a cohort of 26 patients and description of novel noncoding variants of RBM8A. Hum Mutat 2020; 41:1220-1225. [PMID: 32227665 DOI: 10.1002/humu.24021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/18/2020] [Accepted: 03/22/2020] [Indexed: 11/07/2022]
Abstract
Thrombocytopenia-absent radius (TAR) syndrome is characterized by radial defect and neonatal thrombocytopenia. It is caused by biallelic variants of RBM8A gene (1q21.1) with the association of a null allele and a hypomorphic noncoding variant. RBM8A encodes Y14, a core protein of the exon junction complex involved in messenger RNA maturation. To date, only two hypomorphic variants have been identified. We report on a cohort of 26 patients affected with TAR syndrome and carrying biallelic variants in RBM8A. Half patients carried a 1q21.1 deletion and one of the two known hypomorphic variants. Four novel noncoding variants of RBM8A were identified in the remaining patients. We developed experimental models enabling their functional characterization in vitro. Two variants, located respectively in the 5'-untranslated region (5'-UTR) and 3'-UTR regions, are responsible for a diminished expression whereas two intronic variants alter splicing. Our results bring new insights into the molecular knowledge of TAR syndrome and enabled us to propose genetic counseling for patients' families.
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Affiliation(s)
- Simon Boussion
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
| | - Fabienne Escande
- EA7364-RADEME, Lille University, Lille, France
- Biochemistry and Molecular Oncology Laboratory, CHU Lille, Lille, France
| | - Anne-Sophie Jourdain
- EA7364-RADEME, Lille University, Lille, France
- Biochemistry and Molecular Oncology Laboratory, CHU Lille, Lille, France
| | - Thomas Smol
- EA7364-RADEME, Lille University, Lille, France
- Medical Genetics Department, CHU Lille, Lille, France
| | - Perrine Brunelle
- EA7364-RADEME, Lille University, Lille, France
- Biochemistry and Molecular Oncology Laboratory, CHU Lille, Lille, France
| | | | - Yves Alembik
- Medical Genetics Department, CHU Strasbourg, Strasbourg, France
| | - Tania Attié-Bitach
- Histology, Embryology and Cytogenetics Department, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Geneviève Baujat
- Clinical Genetics Department, Necker-Enfants Malades Hospital, AP-HP, INSERM UMR, IMAGINE Institute, Paris, France
| | - Anne Bazin
- Antenatal Diagnosis Department, René Dubois Hospital, Pontoise, France
| | - Maryse Bonnière
- Histology, Embryology and Cytogenetics Department, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | | | | | - Louise Devisme
- EA7364-RADEME, Lille University, Lille, France
- Anatomo-Pathology Institute, CHU Lille, Lille, France
| | - Cyril Goizet
- Medical Genetics Department, CHU Bordeaux, MRGM Laboratory, INSERM, Bordeaux University, Bordeaux, France
| | - Alice Goldenberg
- Genetics Department, Reference Center for Developmental Anomalies, CHU Rouen, Rouen, France
| | - Sarah Grotto
- Genetics Department, Robert Debré Hospital, AP-HP, Paris, France
| | | | | | | | - Charlotte Mechler
- Foetopathology Department, Robert Debré Hospital, AP-HP, Paris, France
| | - Caroline Michot
- Clinical Genetics Department, Necker-Enfants Malades Hospital, AP-HP, INSERM UMR, IMAGINE Institute, Paris, France
| | - Fanny Pelluard
- INSERM U1053-UMR BaRITOn, Foetopathology Department, Pellegrin Hospital, CHU Bordeaux, Bordeaux, France
| | - Audrey Putoux
- Genetics Department, Hospices Civils de Lyon, Lyon, France
- GENDEV Team, CRNL, INSERM U1028, CNRS UMR 5292, UCBL1, Lyon, France
| | - Sandra Whalen
- Clinical Genetics, Reference Center for Developmental Anomalies, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Jamal Ghoumid
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
| | - Sylvie Manouvrier-Hanu
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
| | - Florence Petit
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
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Bottillo I, Castori M, De Bernardo C, Fabbri R, Grammatico B, Preziosi N, Scassellati GS, Silvestri E, Spagnuolo A, Laino L, Grammatico P. Prenatal diagnosis and post-mortem examination in a fetus with thrombocytopenia-absent radius (TAR) syndrome due to compound heterozygosity for a 1q21.1 microdeletion and a RBM8A hypomorphic allele: a case report. BMC Res Notes 2013; 6:376. [PMID: 24053387 PMCID: PMC3849061 DOI: 10.1186/1756-0500-6-376] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 09/17/2013] [Indexed: 11/14/2022] Open
Abstract
Background Thrombocytopenia–absent radius syndrome is a rare autosomal recessive disorder characterized by megakaryocytic thrombocytopenia and longitudinal limb deficiencies mostly affecting the radial ray. Most patients are compound heterozygotes for a 200 kb interstitial microdeletion in 1q21.1 and a hypomorphic allele in RBM8A, mapping in the deleted segment. At the moment, the complete molecular characterization of thrombocytopenia–absent radius syndrome is limited to a handful of patients mostly ascertained in the pediatric age Case presentation We report on a fetus with bilateral upper limb deficiency found at standard prenatal ultrasound examination. The fetus had bilateral radial agenesis and humeral hypo/aplasia with intact thumbs, micrognathia and urinary anomalies, indicating thrombocytopenia–absent radius syndrome. Molecular studies demonstrated compound heterozygosity for the 1q21.1 microdeletion and the RBM8A rs139428292 variant at the hemizygous state, inherited from the mother and father, respectively Conclusion The molecular information allowed prenatal diagnosis in the following pregnancy resulting in the birth of a healthy carrier female. A review was carried out with the attempt to the trace the fetal ultrasound presentation of thrombocytopenia–absent radius syndrome and discussing opportunities for second-tier molecular studies within a multidisciplinary setting.
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Affiliation(s)
- Irene Bottillo
- Department of Molecular Medicine, Medical Genetics, San Camillo-Forlanini Hospital, Sapienza University, Rome, Italy.
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3
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Albers CA, Newbury-Ecob R, Ouwehand WH, Ghevaert C. New insights into the genetic basis of TAR (thrombocytopenia-absent radii) syndrome. Curr Opin Genet Dev 2013; 23:316-23. [PMID: 23602329 DOI: 10.1016/j.gde.2013.02.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/15/2013] [Accepted: 02/25/2013] [Indexed: 12/31/2022]
Abstract
Thrombocytopenia with absent radii (TAR) syndrome is a rare disorder combining specific skeletal abnormalities with a reduced platelet count. Rare proximal microdeletions of 1q21.1 are found in the majority of patients but are also found in unaffected parents. Recently it was shown that TAR syndrome is caused by the compound inheritance of a low-frequency noncoding SNP and a rare null allele in RBM8A, a gene encoding the exon-junction complex subunit member Y14 located in the deleted region. This finding provides new insight into the complex inheritance pattern and new clues to the molecular mechanisms underlying TAR syndrome. We discuss TAR syndrome in the context of abnormal phenotypes associated with proximal and distal 1q21.1 microdeletion and microduplications with incomplete penetrance and variable expressivity.
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Köken G, Akbaş P, Coşar E. Prenatal diagnosis of thrombocytopenia-absent radius syndrome. CASE REPORTS IN PERINATAL MEDICINE 2012. [DOI: 10.1515/crpm-2011-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The prenatal diagnosis of thrombocytopenia-absent radius (TAR) syndrome by ultrasound is established. The sonographic findings showed bilateral absence of the radii and club hands with normal thumbs and metacarpals. Thrombocytopenia was identified from the postabortal cord blood. Three-dimensional computerized tomography images confirmed the sonographic diagnosis. This report, to our knowledge, is one of the few cases published in the literature about the prenatal diagnosis of TAR syndrome.
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Affiliation(s)
- Gülengül Köken
- Department of Obstetrics and Gynecology, Faculty of Medicine, Afyon Kocatepe University, Afyonkarahisar, Turkey
| | - Pınar Akbaş
- Department of Obstetrics and Gynecology, Faculty of Medicine, Afyon Kocatepe University, Afyonkarahisar, Turkey
| | - Emine Coşar
- Department of Obstetrics and Gynecology, Faculty of Medicine, Çanakkale 18 Mart University, Terzioğlu Yerleşkesi, 17100 Çanakkale, Turkey
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Fiedler J, Strauss G, Wannack M, Schwiebert S, Seidel K, Henning K, Klopocki E, Schmugge M, Gaedicke G, Schulze H. Two patterns of thrombopoietin signaling suggest no coupling between platelet production and thrombopoietin reactivity in thrombocytopenia-absent radii syndrome. Haematologica 2011; 97:73-81. [PMID: 21933853 DOI: 10.3324/haematol.2011.049619] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Thrombocytopenia with absent radii syndrome is defined by bilateral radius aplasia and thrombocytopenia. Due to impaired thrombopoietin signaling there are only few bone marrow megakaryocytes and these are immature; the resulting platelet production defect improves somewhat over time. A microdeletion on chromosome 1q21 is present in all patients but is not sufficient to form thrombocytopenia with absent radii syndrome. We aimed to refine the signaling defect in this syndrome. DESIGN AND METHODS We report an extended study of 23 pediatric and adult patients suffering from thrombocytopenia with absent radii syndrome in order to scrutinize thrombopoietin signal transduction by immunoblotting and gel electrophoretic shift assays. In addition, platelet immunotyping and reactivity were analyzed by flow cytometry. Results were correlated with clinical data including age and platelet counts. RESULTS Two distinct signaling patterns were identified. Juvenile patients showed abrogated thrombopoietin signaling (pattern #1), which is restored in adults (pattern #2). Phosphorylated Jak2 was indicative of activation of STAT1, 3 and 5, Tyk2, ERK, and Akt, showing its pivotal role in distinct thrombopoietin-dependent pathways. Jak2 cDNA was not mutated and the thrombopoietin receptor was present on platelets. All platelets of patients expressed normal levels of CD41/61, CD49b, and CD49f receptors, while CD42a/b and CD29 were slightly reduced and the fibronectin receptor CD49e markedly reduced. Lysosomal granule release in response to thrombin receptor activating peptide was diminished. CONCLUSIONS We show a combined defect of platelet production and function in thrombocytopenia with absent radii syndrome. The rise in platelets that most patients have during the first years of life preceded the restored thrombopoietin signaling detected at a much later age, implying that these events are uncoupled and that an unknown factor mediates the improvement of platelet production.
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Houeijeh A, Andrieux J, Saugier-Veber P, David A, Goldenberg A, Bonneau D, Fouassier M, Journel H, Martinovic J, Escande F, Devisme L, Bisiaux S, Chaffiotte C, Baux M, Kerckaert JP, Holder-Espinasse M, Manouvrier-Hanu S. Thrombocytopenia-absent radius (TAR) syndrome: a clinical genetic series of 14 further cases. impact of the associated 1q21.1 deletion on the genetic counselling. Eur J Med Genet 2011; 54:e471-7. [PMID: 21635976 DOI: 10.1016/j.ejmg.2011.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
Thrombocytopenia-absent radius Syndrome (TAR) is a rare congenital malformation syndrome of complicated transmission. 1q21.1 deletion is necessary but not sufficient for its expression. We report the result of a French multicentric clinical study, and we emphasized on the role of the associated 1q21.1 deletion in the diagnosis and the genetic counselling of our patients. We gathered information on 14 patients presenting with TAR syndrome and referred for genetic counselling in six different university hospitals (8 foetuses, 1 child and 5 adults). Clinical or pathology details, as well as skeletal X-rays were analyzed. Genetic studies were performed by Array-CGH, and Quantitative Multiplex PCR. We demonstrated the very variable phenotypes of TAR syndrome. Female:male ratio was ∼2:1. All patients presented with bilateral radial aplasia/hypoplasia with preserved thumbs. Phocomelia and lower limb anomalies were present in 28% of the cases. We reported the first case of cystic hygroma on affected foetus. 1q21.1 deletions ranging from 330 to 1100 kb were identified in all affected patients. Most of them were inherited from one healthy parent (80%). The identification of a 1q21.1 deletion allowed confirmation of TAR syndrome diagnosis, particularly in foetuses and in atypical phenotypes. Additionally, it allowed accurate genetic counselling, especially when it occurred de novo. These findings allowed discussing the diagnostic criteria and management towards TAR syndrome.
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Affiliation(s)
- Ali Houeijeh
- Service de Génétique clinique Guy Fontaine, CHRU Lille, France
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Klopocki E, Schulze H, Strauss G, Ott CE, Hall J, Trotier F, Fleischhauer S, Greenhalgh L, Newbury-Ecob RA, Neumann LM, Habenicht R, König R, Seemanova E, Megarbane A, Ropers HH, Ullmann R, Horn D, Mundlos S. Complex inheritance pattern resembling autosomal recessive inheritance involving a microdeletion in thrombocytopenia-absent radius syndrome. Am J Hum Genet 2007; 80:232-40. [PMID: 17236129 PMCID: PMC1785342 DOI: 10.1086/510919] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 11/14/2006] [Indexed: 11/03/2022] Open
Abstract
Thrombocytopenia-absent radius (TAR) syndrome is characterized by hypomegakaryocytic thrombocytopenia and bilateral radial aplasia in the presence of both thumbs. Other frequent associations are congenital heart disease and a high incidence of cow's milk intolerance. Evidence for autosomal recessive inheritance comes from families with several affected individuals born to unaffected parents, but several other observations argue for a more complex pattern of inheritance. In this study, we describe a common interstitial microdeletion of 200 kb on chromosome 1q21.1 in all 30 investigated patients with TAR syndrome, detected by microarray-based comparative genomic hybridization. Analysis of the parents revealed that this deletion occurred de novo in 25% of affected individuals. Intriguingly, inheritance of the deletion along the maternal line as well as the paternal line was observed. The absence of this deletion in a cohort of control individuals argues for a specific role played by the microdeletion in the pathogenesis of TAR syndrome. We hypothesize that TAR syndrome is associated with a deletion on chromosome 1q21.1 but that the phenotype develops only in the presence of an additional as-yet-unknown modifier (mTAR).
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Affiliation(s)
- Eva Klopocki
- Institut für Medizinische Genetik, Charité Universitätsmedizin Berlin, Berlin, Germany
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8
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Geddis AE. Inherited Thrombocytopenia: Congenital Amegakaryocytic Thrombocytopenia and Thrombocytopenia With Absent Radii. Semin Hematol 2006; 43:196-203. [PMID: 16822462 DOI: 10.1053/j.seminhematol.2006.04.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Thrombocytopenia in the newborn period can signify an inherited platelet disorder. Congenital amegakaryocytic thrombocytopenia (CAMT) and thrombocytopenia with absent radii (TAR) share features of isolated thrombocytopenia, reduced or absent marrow megakaryocytes, impaired responsiveness to thrombopoietin (TPO), and high plasma TPO levels. These disorders are most readily distinguished from each other by the finding of radial aplasia in TAR and the presence of c-MPL mutations in CAMT. In addition, their long-term outcomes are strikingly different: the development of trilineage marrow failure in CAMT in contrast to the general improvement of thrombocytopenia in TAR. The differential diagnosis for CAMT and TAR also includes other congenital disorders in which thrombocytopenia and radial abnormalities can be seen. In this article we will review our molecular and clinical understanding of these two inherited disorders of amegakaryocytosis.
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Affiliation(s)
- Amy E Geddis
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, University of California San Diego, La Jolla, CA, USA.
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9
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Greenhalgh KL, Howell RT, Bottani A, Ancliff PJ, Brunner HG, Verschuuren-Bemelmans CC, Vernon E, Brown KW, Newbury-Ecob RA. Thrombocytopenia-absent radius syndrome: a clinical genetic study. J Med Genet 2002; 39:876-81. [PMID: 12471199 PMCID: PMC1757221 DOI: 10.1136/jmg.39.12.876] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The thrombocytopenia-absent radius (TAR) syndrome is a congenital malformation syndrome characterised by bilateral absence of the radii and a thrombocytopenia. The lower limbs, gastrointestinal, cardiovascular, and other systems may also be involved. Shaw and Oliver in 1959 were the first to describe this condition, but it was Hall et al in 1969 who reported the first major series of patients. Since then most reports have been based on single or small numbers of cases. We report the results of a clinical study looking at the phenotype of 34 patients with TAR syndrome. All cases had a documented thrombocytopenia and bilateral radial aplasia, 47% had lower limb anomalies, 47% cow's milk intolerance, 23% renal anomalies, and 15% cardiac anomalies. Congenital anomalies not previously described in association with TAR syndrome included facial capillary haemangiomata, intracranial vascular malformation, sensorineural hearing loss, and scoliosis. Karyotype analysis, chromosome breakage studies including premature centromeric separation and fluorescence in situ hybridisation studies looking for a deletion of chromosome 22q11 were undertaken. Two abnormal karyotypes were identified.
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Affiliation(s)
- K L Greenhalgh
- Department of Clinical Genetics, Level B, St Michael's Hill, Southwell Street, Bristol BS2 8EG, UK
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Tongsong T, Sirichotiyakul S, Chanprapaph P. Prenatal diagnosis of thrombocytopenia-absent-radius (TAR) syndrome. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2000; 15:256-258. [PMID: 10846784 DOI: 10.1046/j.1469-0705.2000.00047.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The prenatal diagnosis of thrombocytopenia-absent-radius (TAR) syndrome using ultrasound and cordocentesis in the 16th week of gestation is established. The sonographic findings detected in this case included bilateral absence of the radius and club hands with normal thumbs and metacarpals. Because of a high index of suspicion for the syndrome, cordocentesis for fetal blood analysis was performed. Thrombocytopenia, with a platelet count of 14,000/mm3, was identified. The pregnancy was electively terminated and subsequent findings confirmed the sonographic diagnosis. This report, to our knowledge, is one of a very limited number of cases published in the literature, in which the prenatal diagnosis of TAR syndrome was made.
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Affiliation(s)
- T Tongsong
- Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Thailand
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11
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Urban M, Opitz C, Bommer C, Enders H, Tinschert S, Witkowski R. Bilaterally cleft lip, limb defects, and haematological manifestations: Roberts syndrome versus TAR syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 1998; 79:155-60. [PMID: 9788553 DOI: 10.1002/(sici)1096-8628(19980923)79:3<155::aid-ajmg1>3.0.co;2-m] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report on a 13-year-old patient followed since birth. He is the only offspring of young, non-consanguineous German parents. His mother has an isolated left cleft of lip and a cleft palate. At birth, our patient presented with bilaterally cleft lip/cleft palate, phocomelia of upper limbs with normal hands, and mild symmetrical deficiencies of the long bones of the lower limbs. Haematological evaluation demonstrated a leukaemoid reaction during a urinary tract infection as well as intermittent thrombocytopenia and episodes of marked eosinophilia during the first two years of life. Intellectual development has been normal. Comparison with two similar cases from the literature suggests a non-random phenotypic overlap of Roberts syndrome (MIM 268300) and TAR syndrome (MIM 274000). Such clinical constellations may be key observations to understand the genetic relationship of Roberts syndrome and TAR syndrome in future phenotype-genotype correlations.
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Affiliation(s)
- M Urban
- Institut für Medizinische Genetik, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Germany
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12
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Sekine I, Hagiwara T, Miyazaki H, Hirayama K, Dobashi H, Kogawa K, Yoshioka S. Thrombocytopenia with absent radii syndrome: studies on serum thrombopoietin levels and megakaryopoiesis in vitro. J Pediatr Hematol Oncol 1998; 20:74-8. [PMID: 9482417 DOI: 10.1097/00043426-199801000-00012] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE The pathogenesis of thrombocytopenia in patients with thrombocytopenia with absent radii (TAR) syndrome has not been clarified yet. PATIENTS AND METHODS This is the first report of a Japanese patient with TAR syndrome. We studied his megakaryopoiesis in vitro and serum levels of thrombopoietin (TPO). RESULTS Serum levels of TPO in the patient with TAR syndrome were comparable with those of an age-matched control. The bone marrow cells from the patient with TAR syndrome actually generated megakaryocyte colonies in the presence of TPO and the numbers were significantly greater than those from the age-matched control marrow. However, megakaryocyte colonies from the marrow cells with TAR syndrome contained a much lower number of cells per colony and the size of the individual megakaryocytes appeared to be smaller. CONCLUSION These data suggest that megakaryocyte progenitors from patients with TAR syndrome may have decreased proliferative and differentiative capacity to respond to TPO, leading to thrombocytopenia.
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Affiliation(s)
- I Sekine
- Department of Pediatrics, National Defense Medical College, Tokorozawa, Saitama, Japan
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13
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Labrune P, Pons JC, Khalil M, Mirlesse V, Imbert MC, Odièvre M, Daffos F, Tchernia G, Frydman R. Antenatal thrombocytopenia in three patients with TAR (thrombocytopenia with absent radii) syndrome. Prenat Diagn 1993; 13:463-6. [PMID: 8372072 DOI: 10.1002/pd.1970130607] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Three fetuses with TAR (thrombocytopenia with absent radii) or TAR variant syndrome were found to be thrombocytopenic during the third trimester of the pregnancy. These findings indicate that fetal blood sampling, besides ultrasonography, skeletal radiographs, or even fetoscopy, may indeed contribute to the prenatal diagnosis of TAR syndrome, and thus may help in differentiating TAR syndrome from other syndromes with malformations of the upper limbs.
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Affiliation(s)
- P Labrune
- Service de Pédiatrie and Consultation de Génétique, Hôpital Antoine Béclère, Clamart, France
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14
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van Haeringen A, Veenstra F, Maaswinkel-Mooij PD, van de Kamp JJ. Intermittent thrombocytopenia and absent radii: report of a patient with additional unusual manifestations. AMERICAN JOURNAL OF MEDICAL GENETICS 1989; 34:202-6. [PMID: 2816998 DOI: 10.1002/ajmg.1320340214] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We report on a boy with absent radii and intermittent thrombocytopenia. He has many other manifestations of the thrombocytopenia absent radius (TAR) syndrome but in addition has manifestations not previously described: palatoschisis of the soft palate, subcricoid stenosis, duodenal atresia and extreme sensitivity of chromosomes to X-rays. Our patient could either represent a unique condition or unusual variability of TAR syndrome.
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Affiliation(s)
- A van Haeringen
- Clinical Genetics Center, University Hospital Leiden, The Netherlands
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