eMedicine Specialties > Pediatrics: General Medicine > Hematology

Thrombocytopenia-Absent Radius Syndrome: Differential Diagnoses & Workup

Author: John K Wu, MBBS, MSc, FRCP(C), Clinical Professor, Department of Pediatrics, Division of Hematology-Oncology-BMT, University of British Columbia, Canada
Coauthor(s): Michelle P Wong, MD, Staff Physician, Department of Hematopathology, University of British Columbia Faculty of Medicine, Canada; Suzan Williams, MD, MSc, FRCPC, Staff Physician, Division of Hematology, The Hospital for Sick Children, Canada
Contributor Information and Disclosures

Updated: Sep 17, 2009

Differential Diagnoses

Fanconi Syndrome
Holt-Oram Syndrome

Other Problems to Be Considered

  • RAPADILINO syndrome: RAPADILINO syndrome is a rare syndrome characterized by radial hypoplasia or aplasia, patellar hypoplasia or aplasia, cleft or highly arched palate, diarrhea, dislocated joints, small size (>2 standard deviations below the mean in height), limb malformation, slender nose, and normal intelligence.
  • Roberts syndrome: Roberts syndrome is characterized by prenatal and postnatal growth retardation; craniofacial anomalies, especially facial clefts; limb deficiencies, including tetraphocomelia in most patients; and genital hyperplasia. Parental consanguinity rate is high.
  • Thalidomide embryopathy: Thalidomide embryopathy is the teratogenic effect of thalidomide when the drug is taken during pregnancy. Affected infants can have limb and digit defects, craniofacial anomalies, hearing and vision defects, and improper formation of organs including the heart and kidneys.
  • Trisomy 18 (Edward syndrome): Patients with trisomy 18 may have craniofacial anomalies (eg, prominent occiput, short palpebral fissures, micrognathia, external ear variations); digit anomalies (eg, clenched fist with the index finger overlapping the third finger, the fifth finger overlapping the fourth, hypoplastic nails, thumb aplasia); short sternum (breastbone); rocker-bottom feet; and cardiac, pulmonary, GI, and genitourinary defects.
  • VACTERL association: This is a syndrome of congenital anomalies that includes vertebral dysgenesis, anal atresia with or without fistula, cardiac defects (ventricular septal defect [VSD]), tracheoesophageal fistula, and renal and limb anomalies.

Workup

Laboratory Studies

The following studies are indicated in thrombocytopenia-absent radius (TAR) syndrome:

  • CBC count
    • The platelet count may be 15-30 X 109/L.
    • Eosinophilia is observed in 50% of patients.
    • Leukocytosis may be present, with a WBC count >35 X 109/L with a left shift and leukemoid reaction.
    • Anemia may be present secondary to bleeding.
  • Genetic findings
    • Chromosomes are normal.
    • Findings on chromosomal breakage studies with clastogenic agents are normal.

Imaging Studies

  • Characteristic skeletal involvement (ie, absent radii) is detectable during prenatal transvaginal ultrasonography as early as 13 weeks' gestation, when sufficient fetal skeletal ossification is present.
  • Upper-limb abnormalities on prenatal sonograms suggest numerous syndromes in the differential diagnosis.
  • After radial aplasia is observed, ultrasonography of the extremities, face, and kidneys is indicated.

Other Tests

  • Sampling of the bone marrow reveals the following findings:
    • Normal or hypercellular bone marrow
    • Decreased, absent, or immature megakaryocytes
    • Small, basophilic, vacuolated megakaryocytes
    • Erythroid hyperplasia

Procedures

  • Cordocentesis can be performed to confirm known genetic conditions. Cordocentesis poses a 1-2% risk of fetal loss and a risk of prolonged bleeding from the umbilical puncture site.
  • Weinblatt and associates performed in utero platelet transfusion of a fetus with radial aplasia at 37 weeks' gestation after cordocentesis revealed a platelet count of 40 X 109/L.12 The infant was delivered within 24 hours of the transfusion with no complications.

More on Thrombocytopenia-Absent Radius Syndrome

Overview: Thrombocytopenia-Absent Radius Syndrome
Differential Diagnoses & Workup: Thrombocytopenia-Absent Radius Syndrome
Treatment & Medication: Thrombocytopenia-Absent Radius Syndrome
Follow-up: Thrombocytopenia-Absent Radius Syndrome
Multimedia: Thrombocytopenia-Absent Radius Syndrome
References
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References

  1. Ballmaier M, Schulze H, Strauss G, et al. Thrombopoietin in patients with congenital thrombocytopenia and absent radii: elevated serum levels, normal receptor expression, but defective reactivity to thrombopoietin. Blood. Jul 15 1997;90(2):612-9. [Medline]. [Full Text].

  2. Sekine I, Hagiwara T, Miyazaki H, et al. Thrombocytopenia with absent radii syndrome: studies on serum thrombopoietin levels and megakaryopoiesis in vitro. J Pediatr Hematol Oncol. Jan-Feb 1998;20(1):74-8. [Medline].

  3. Letestu R, Vitrat N, Masse A, et al. Existence of a differentiation blockage at the stage of a megakaryocyte precursor in the thrombocytopenia and absent radii (TAR) syndrome. Blood. Mar 1 2000;95(5):1633-41. [Medline]. [Full Text].

  4. Geddis AE. Congenital amegakaryocytic thrombocytopenia and thrombocytopenia with absent radii. Hematol Oncol Clin North Am. Apr 2009;23(2):321-31. [Medline].

  5. Fleischman RA, Letestu R, Mi X, et al. Absence of mutations in the HoxA10, HoxA11 and HoxD11 nucleotide coding sequences in thrombocytopenia with absent radius syndrome. Br J Haematol. Feb 2002;116(2):367-75. [Medline].

  6. Klopocki E, Schulze H, Strauss G, et al. Complex inheritance pattern resembling autosomal recessive inheritance involving a microdeletion in thrombocytopenia-absent radius syndrome. Am J Hum Genet. Feb 2007;80(2):232-40. [Medline].

  7. Hedberg VA, Lipton JM. Thrombocytopenia with absent radii. A review of 100 cases. Am J Pediatr Hematol Oncol. Spring 1988;10(1):51-64. [Medline].

  8. Greenhalgh KL, Howell RT, Bottani A, et al. Thrombocytopenia-absent radius syndrome: a clinical genetic study. J Med Genet. Dec 2002;39(12):876-81. [Medline]. [Full Text].

  9. Hall JG, Levin J, Kuhn JP, et al. Thrombocytopenia with absent radius (TAR). Medicine (Baltimore). Nov 1969;48(6):411-39. [Medline].

  10. Sachdev P. Brief psychosis in thrombocytopenia-absent radius syndrome: a case report. Aust N Z J Psychiatry. Sep 2005;39(9):841-2. [Medline].

  11. Skorka A, Bielicka-Cymermann J, Gieruszczak-Bialek D, Korniszewski L. Thrombocytopenia-absent radius (tar) syndrome: a case with agenesis of corpus callosum, hypoplasia of cerebellar vermis and horseshoe kidney. Genet Couns. 2005;16(4):377-82. [Medline].

  12. Weinblatt M, Petrikovsky B, Bialer M, et al. Prenatal evaluation and in utero platelet transfusion for thrombocytopenia absent radii syndrome. Prenat Diagn. Sep 1994;14(9):892-6. [Medline].

  13. Dempfle CE, Burck C, Grutzmacher T et al. Increase in platelet count in response to rHuEpo in patient with thromboctopenia and absent radii syndrome. Blood. 2001;97 (7):2189-90. [Medline]. [Full Text].

  14. Aquino VM, Mustafa MM, Vackus L et al. Recombinant interleukin-6 in the treatment of congenital thrombocytopenia associated with absent radii. J Pediatr Hematol Oncol. 1998;20 (5):474-6. [Medline].

  15. Fadoo Z, Naqvi SM. Acute myeloid leukemia in a patient with thrombocytopenia with absent radii syndrome. J Pediatr Hematol Oncol. Feb 2002;24(2):134-5. [Medline].

  16. [Guideline] Finnish Medical Society Duodecim. Thrombocytopenia. In: EBM Guidelines. Evidence-Based Medicine [Internet]. Helsinki, Finland: Wiley Interscience. John Wiley & Sons; 2007 Apr 27. [Full Text].

  17. MacDonald MR, Schaefer GB, Olney AH, Patton DF. Hypoplasia of the cerebellar vermis and corpus callosum in thrombocytopenia with absent radius syndrome on MRI studies. Am J Med Genet. Mar 1 1994;50(1):46-50. [Medline].

  18. McLaurin TM, Bukrey CD, Lovett RJ, Mochel DM. Management of thrombocytopenia-absent radius (TAR) syndrome. J Pediatr Orthop. May-Jun 1999;19(3):289-96. [Medline].

  19. Urban M, Opitz C, Bommer C, et al. Bilaterally cleft lip, limb defects, and haematological manifestations: Roberts syndrome versus TAR syndrome. Am J Med Genet. Sep 23 1998;79(3):155-60. [Medline].

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Further Reading

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Keywords

thrombocytopenia-absent radius syndrome, TAR syndrome, tetraphocomelia-thrombocytopenia syndrome, hypomegakaryocytic thrombocytopenia, absent radii, gene, gene, rubella, Roberts syndrome, cow's milk allergy, purpura, petechiae, epistaxis, melena, hemoptysis, hematuria, hematemesis, mental retardation, diarrhea, bilateral radial aplasia, radial club hand, hypoplastic carpals and phalanges, hypoplastic ulnae, humeri, shoulder girdles, syndactyly, clinodactyly, hip dislocation, femoral torsion, tetralogy of Fallot, atrial septal defect, ventricular septal defect, VSD, micrognathia, hypertelorism, Meckel diverticulum, hyperhidrosis, short stature, Fanconi anemia, Blackfan-Diamond syndrome, treatment, diagnosis

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Contributor Information and Disclosures

Author

John K Wu, MBBS, MSc, FRCP(C), Clinical Professor, Department of Pediatrics, Division of Hematology-Oncology-BMT, University of British Columbia, Canada
John K Wu, MBBS, MSc, FRCP(C) is a member of the following medical societies: American Society of Hematology and Canadian Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Michelle P Wong, MD, Staff Physician, Department of Hematopathology, University of British Columbia Faculty of Medicine, Canada
Disclosure: Nothing to disclose.

Suzan Williams, MD, MSc, FRCPC, Staff Physician, Division of Hematology, The Hospital for Sick Children, Canada
Suzan Williams, MD, MSc, FRCPC is a member of the following medical societies: American Academy of Pediatrics, American Society of Hematology, Canadian Medical Association, Canadian Paediatric Society, College of Physicians and Surgeons of Ontario, Ontario Medical Association, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Medical Editor

J Martin Johnston, MD, Associate Professor of Pediatrics, Mercer University School of Medicine; Director of Pediatric Hematology/Oncology, Backus Children's Hospital; Consulting Oncologist/Hematologist, St Damien's Pediatric Hospital
J Martin Johnston, MD is a member of the following medical societies: American Society of Pediatric Hematology/Oncology
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

James L Harper, MD, Associate Professor, Department of Pediatrics, Division of Hematology/Oncology and Bone Marrow Transplantation, Associate Chairman for Education, Department of Pediatrics, University of Nebraska Medical Center; Assistant Clinical Professor, Department of Pediatrics, Creighton University; Director, Continuing Medical Education, Children's Memorial Hospital; Pediatric Director, Nebraska Regional Hemophilia Treatment Center
James L Harper, MD is a member of the following medical societies: American Academy of Pediatrics, American Association for Cancer Research, American Federation for Clinical Research, American Society of Hematology, American Society of Pediatric Hematology/Oncology, Council on Medical Student Education in Pediatrics, and Hemophilia and Thrombosis Research Society
Disclosure: Nothing to disclose.

CME Editor

Helen SL Chan, MBBS, FRCP(C), FAAP, Senior Scientist, Research Institute; Professor, Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Canada
Helen SL Chan, MBBS, FRCP(C), FAAP is a member of the following medical societies: American Academy of Pediatrics, American Association for Cancer Research, American Society of Hematology, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Chief Editor

Robert J Arceci, MD, PhD, King Fahd Professor of Pediatric Oncology, Professor of Pediatrics, Oncology and the Cellular and Molecular Medicine Graduate Program, Kimmel Comprehensive Cancer Center at Johns Hopkins University School of Medicine
Robert J Arceci, MD, PhD is a member of the following medical societies: American Association for Cancer Research, American Association for the Advancement of Science, American Pediatric Society, American Society of Hematology, and American Society of Pediatric Hematology/Oncology
Disclosure: Nothing to disclose.

 
 
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