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- $Unique_ID{BRK04268}
- $Pretitle{}
- $Title{Thrombocytopenia-Absent Radius Syndrome}
- $Subject{Thrombocytopenia-Absent Radius Syndrome TAR Syndrome
- Thrombocytopenia-Absent Radii Syndrome Radial Aplasia-Thrombocytopenia
- Syndrome Radial Aplasia-Amegakaryocytic Thrombocytopenia Syndrome Fanconi's
- Anemia}
- $Volume{}
- $Log{}
-
- Copyright (C) 1989 National Organization for Rare Disorders, Inc.
-
- 657:
- Thrombocytopenia-Absent Radius Syndrome
-
- ** IMPORTANT **
- It is possible that the main title of the article (Thrombocytopenia-
- Absent Radius Syndrome) is not the name you expected. Please check the
- SYNONYM listing to find the alternate names and disorder subdivisions covered
- by this article.
-
- Synonyms
-
- TAR Syndrome
- Thrombocytopenia-Absent Radii Syndrome
- Radial Aplasia-Thrombocytopenia Syndrome
- Radial Aplasia-Amegakaryocytic Thrombocytopenia Syndrome
-
- Information on the following disease can be found in the Related
- Disorders section of this report:
-
- Fanconi's Anemia
-
- General Discussion
-
- ** REMINDER **
- The information contained in the Rare Disease Database is provided for
- educational purposes only. It should not be used for diagnostic or treatment
- purposes. If you wish to obtain more information about this disorder, please
- contact your personal physician and/or the agencies listed in the "Resources"
- section of this report.
-
- Thrombocytopenia-Absent Radius (TAR) Syndrome is a genetic disorder
- characterized by a very low level of the number of blood platelets
- (thrombocytopenia) and the absence or underdevelopment of one of the short
- bones (radius) in the arm.
-
- Symptoms
-
- The very low level of the number of blood platelets (thrombocytopenia) is
- most severe during early infancy of TAR Syndrome patients. Thrombocytopenia
- may cause excessive bleeding from the skin, mucous membranes (thin moist
- layer lining the body's cavity), or within the skull (intracranial). Other
- blood disorders may also occur: absent or underdeveloped blood platelet
- precursors (megakaryocytes); a high number of a type of white blood cells
- (eosinophilia); leukemia-like levels of the number of white blood cells
- (granulocytosis); and (anemia). TAR infants are more likely to develop an
- intolerance to cow milk.
-
- One of the two short bones (the radius) of the arm is absent or
- underdeveloped and it usually involves both arms. It may be associated with
- the underdevelopment of the other short bone (the ulna) of the arm and
- defects of the hands, legs, and/or feet.
-
- Short stature, bowed legs, shortened long bone of the arm (humerus),
- underdeveloped shoulder girdle (several bones that support the arms), and
- dislocation of the hip may also be present. Kidney or heart defects, a
- purplish birthmark (nevus flammeus) on the forehead, and spina bifida
- (incomplete closure of vertebrae in the spinal column) may also be present.
-
- Causes
-
- TAR Syndrome is inherited as an autosomal recessive trait. (Human traits
- including the classic genetic diseases, are the product of the interaction of
- two genes for that condition, one received from the father and one from the
- mother. In recessive disorders, the condition does not appear unless a
- person inherits the same defective gene for the same trait from each parent.
- If one receives one normal gene and one gene for the disease, the person will
- be a carrier for the disease, but usually will show no symptoms. The risk of
- transmitting the disease to the children of a couple, both of whom are
- carriers for a recessive disorder, is twenty-five percent. Fifty percent of
- their children will be carriers, but healthy as described above. Twenty-five
- percent of their children will receive both normal genes, one from each
- parent, and will be genetically normal.)
-
- Affected Population
-
- TAR Syndrome is a rare disorder that occurs at birth. It affects males and
- females in equal numbers.
-
- Related Disorders
-
- Symptoms of the following disorder can be similar to those of
- Thrombocytopenia-Absent Radius (TAR) Syndrome. Comparisons may be useful for
- a differential diagnosis:
-
- Fanconi's Anemia is a rare hereditary disorder characterized by anemia
- due to defective functioning of the blood-forming organs, bone abnormalities,
- unusually small head, retarded growth and development of the genitalia, and
- brown pigmentation. Excessive bleeding, infections, and leukemia may also
- occur. This disorder is more common in males and is usually detected within
- the first eight years of life. (For more information on this disorder,
- choose "Fanconi" as your search term in the Rare Disease Database).
-
- Therapies: Standard
-
- Early management is necessary for the various blood conditions of TAR
- Syndrome patients. Braces and/or surgery may be necessary for bone
- malformations related to this disorder.
-
- Genetic counseling may be of benefit for patients and their families.
- Other treatment is symptomatic and supportive.
-
- Therapies: Investigational
-
- This disease entry is based upon medical information available through April
- 1989. Since NORD's resources are limited, it is not possible to keep every
- entry in the Rare Disease Database completely current and accurate. Please
- check with the agencies listed in the Resources section for the most current
- information about this disorder.
-
- Resources
-
- For more information on Thrombocytopenia-Absent Radius Syndrome, please
- contact:
-
- National Organization for Rare Disorders (NORD)
- P.O. Box 8923
- New Fairfield, CT 06812-1783
- (203) 746-6518
-
- Thrombocytopenia Absent Radius Syndrome Association (TARSA)
- 312 Sherwood Drive
- R.D. 1
- Linwood, NJ 08221
- (609) 927-0418
-
- NIH/National Institute of Child Health and Human Development (NICHHD)
- 9000 Rockville Pike
- Bethesda, MD 20892
- (301) 496-4236
-
- For Genetic Information and genetic counseling referrals:
-
- March of Dimes Birth Defects Foundation
- 1275 Mamaroneck Avenue
- White Plains, NY 10605
- (914) 428-7100
-
- Alliance of Genetic Support Groups
- 35 Wisconsin Circle, Suite 440
- Chevy Chase, MD 20815
- (800) 336-GENE
- (301) 652-5553
-
- References
-
- MENDELIAN INHERITANCE IN MAN, 7th ed.: Victor A. McKusick; Johns Hopkins
- University Press, 1986. Pp. 1207-1208.
-
- INTERNAL MEDICINE, 2nd Ed.: Jay H. Stein, ed.-in-chief; Little, Brown
- and Co., 1987. Pp. 1008.
-
- SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th ed.: Kenneth L.
- Jones; W.B. Saunders Company, 1988. Pp. 276, 984.
-
- THROMBOCYTOPENIA-ABSENT RADIUS SYNDROME: A.G. Aledo, et al.; An Esp
- Pediatr (January, 1982: issue 16(1)). Pp. 82-87.
-
-