TAR syndrome is a rare genetic disorder characterized by missing or abnormal radii (bones in the forearms) and low platelet counts. It was first observed in 1956 and takes its name from the symptoms of thrombocytopenia (low platelets) and absent radii. Other common features include short stature, hand abnormalities, and heart defects. The condition is inherited in an autosomal recessive pattern and can be diagnosed prenatally. Treatment focuses on managing the thrombocytopenia to prevent bleeding and surgery to correct limb abnormalities.

1. Thrombocytopenia Absent
Radius Syndrome (TAR)
By: Callyn Oshita
Period 5

2. Introduction to TAR Syndrome
• Observed in 1956 by Dr. S. Shaw (Sweet, 2010)
• Named in 1969 by Dr. Judith Hall (Sweet, 2010)
• Affects both males and females equally (Sweet,
2010)
• Occurs in all ethnic and racial groups (Sweet,
2010)
• Less than 1 in 100,000 infants affected
(“Thrombocytopenia-absent”, 2012)
• Other names include: Thrombocytopenia Absent
Radii, Radial Aplasia-Thrombocytopenia
Syndrome, and Radial Aplasia-Amegakaryocytic
Thrombocytopenia (“Thrombocytopenia-absent”,
2012)

3. Symptoms and Treatment
• Born with missing radius (a bone) in each forearm
(“Thrombocytopenia-absent”, 2012)
• Shortage of platelets in blood (Thrombocytopenia)
(“Thrombocytopenia-absent”, 2012)
▫ Blood cannot clot correctly so internal bleeding can cause
death (especially in an infant’s first year) (Sweet, 2010)
▫ Because of the risk for excessive bleeding, affected infants
don’t typically participate in surgeries (Sweet, 2010)
• 1/3 of infants affected have heart defects (Sweet, 2010)
• 40% of affected die in early infancy (excessive bleeding and
heart disease being the main reason for death) (Philippe &
Silva, 1999)
• The thrombocytopenia is treated with platelet transfusions
(Sweet, 2010)
• Thrombocytopenia often improves with age (Sweet, 2010)
• Surgery can be done to straighten the hands (Sweet, 2010)

4. Prevention and Inheritance
• It is an autosomal recessive disorder (two copies
of the gene are required for the trait to be
expressed) (Philippe & Silva, 1999)
• Carriers of the gene do not show signs of the
condition (“Thrombocytopenia-absent”, 2012)
• TAR can be diagnosed during pregnancy
through x-rays showing the shortened arms and
blood samples from the umbilical cord to read
the platelet count
(Sweet, 2010)

5. Personal Reflection
• If I had this disease, assuming I was able to live through the
first two rough years of life, I would probably be discouraged
because of the huge disadvantage you have in terms of
mobility and ability. Many of the affected have shortened and
deformed arms so it is very hard to do even simple things.
Also, you would have to be very careful not to hurt yourself
too much because even if your platelet levels are better than
when you were an infant, they can still be low so you can
bruise easily. Learning about this disease really makes me
thankful for my body the way it is because even if the chances
for getting a condition like this are low, it could still happen.
As for my own family, you can’t really do anything to prevent
this disease but if it is to occur I believe I just need to stay
optimistic and do the best I can to care for my child.

6. References
• Sweet, K. M. (2010). TAR syndrome. In S. L. Blachford (Ed.), The Gale
Encyclopedia of Genetic Disorders. Detroit: Gale. Retrieved March 30,
2014, from
http://ic.galegroup.com/ic/scic/ReferenceDetailsPage/ReferenceDetailsW
indow?failOverType=&query=&prodId=SCIC&windowstate=normal&con
tentModules=&mode=view&displayGroupName=Reference&limiter=&cur
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thin_results=&p=SCIC&action=e&catId=&activityType=&scanId=&docu
mentId=GALE%7CWQVZVS159077383&source=Bookmark&u=san00962
&jsid=7e639b4ca68b0f9a6df95697d7bd49ea
• Thrombocytopenia-absent radius syndrome. (2012, October). Genetics
Home Reference. Retrieved March 30, 2014, from
http://ghr.nlm.nih.gov/condition/thrombocytopenia-absent-radius-
syndrome
• Philippe, J., & Silva, S. (1999, May 1). Thrombocytopenia-absent radius
syndromes. The Fetus. Retrieved March 30, 2014, from
http://sonoworld.com/fetus/page.aspx?id=444