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- $Unique_ID{BRK04292}
- $Pretitle{}
- $Title{Trisomy 18 Syndrome}
- $Subject{Trisomy 18 Syndrome Trisomy 18 Edward's Syndrome Trisomy E Trisomy
- 16-18 }
- $Volume{}
- $Log{}
-
- Copyright (C) 1986, 1992 National Organization for Rare Disorders, Inc.
-
- 217:
- Trisomy 18 Syndrome
-
- ** IMPORTANT **
- It is possible the main title of the Article (Trisomy 18 Syndrome) is not
- the name you expected. Please check the SYNONYMS listing to find the
- alternate names and disorder subdivisions covered by this article.
-
- Synonyms
-
- Trisomy 18
- Edward's Syndrome
- Trisomy E
- Trisomy 16-18
-
- 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.
-
-
- Trisomy 18 Syndrome is a genetic disorder with onset before birth.
- Paternal and maternal age are usually above average. Babies appear thin and
- frail. They fail to thrive and have difficulty feeding. These children show
- generalized increased muscle tension (hypertonicity) with rigidity in flexion
- of the limbs and mental retardation.
-
- Symptoms
-
- The newborn infant with Trisomy 18 is premature or small for its gestational
- age, with markedly retarded development (hypoplasia) of skeletal muscle and
- subcutaneous fat. The baby's cry is weak, and response to sound is
- decreased. There is often a history of feeble fetal activity, excess of
- fluid in the fetal sac, a small placenta, and a single umbilical artery.
-
- The back part of the head is prominent; there is a narrow bifrontal
- diameter with decreased orbital ridges, short eyelid fissures, a small mouth
- and unusually small jaw, all of which give the face a pinched appearance. A
- small head (microcephaly), fold of the eyelid in the lateral corner of the
- eye (epicanthal folds), low-set malformed ears, and cleft lip and/or palate
- are common. The peculiar clenched fist with the index finger overlapping the
- 3rd and 4th fingers is almost distinctive of this disorder. Absence of the
- distal crease on the 5th finger is common as is a low-arch dermal ridge
- pattern on the fingertips. The nails are underdeveloped and the big toe is
- shortened and frequently bent backward (dorsiflexed). Underdeveloped or
- absent thumbs, clubfeet, rocker-bottom feet, and webbed fingers and toes
- (syndactyly) may also occur.
-
- An opening in the ventricular septum of the heart (ventricular septal
- defect), persistent blood vessel connecting the aorta to the pulmonary artery
- (patent ductus arteriosus), an opening in the septum between the two atria in
- the heart (atrial septal defect), and abnormalities in the pulmonary and/or
- aortic valves may be present. (For more information on these defects, please
- see the articles in the Rare Disease Database.)
-
- Congenital anomalies of the lung, diaphragm, kidneys and ureters are
- frequent. Hernias and/or separation of the rectus muscles of the abdominal
- wall, redundant skin folds especially over the back of the neck, and, in
- males, failure of the testes to descend into the scrotum are also common.
- Mental retardation in Trisomy 18 Syndrome is usually severe.
-
- Causes
-
- Trisomy 18 Syndrome is caused by the presence of a third chromosome 18. This
- chromosome is responsible for the physical and mental abnormalities of this
- developmental disorder.
-
- Affected Population
-
- Female infants are affected 3 times greater than male infants with Trisomy 18
- Syndrome. Children with this disorder are generally born to older parents.
-
- Therapies: Standard
-
- Treatment of Trisomy 18 Syndrome is symptomatic and supportive. Special
- education, physical therapy, and other medical, social, or vocational
- services are of benefit to the patient, and are often necessary for the child
- to reach his/her full potential.
-
- Therapies: Investigational
-
- This disease entry is based upon medical information available through
- February 1992. 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 Trisomy 18 Syndrome, please contact:
-
- National Organization for Rare Disorders (NORD)
- P.O. Box 8923
- New Fairfield, CT 06812-1783
- (203) 746-6518
-
- Support Organization for Trisomy 18/13 (SOFT 18/13)
- National Headquarters
- 4625 Lindell Blvd., Suite 501
- St. Louis, MO 63108
- (314) 367-0055
-
- S.O.F.T. Canada Inc.
- 1214 Concession 5 West
- RR2 Waterdown, Ontario LOR 2H2
- (416) 659-3216
-
- NIH/National Institute of Child Health and Human Development
- 9000 Rockville Pike
- Bethesda, MD 20205
- (301) 496-5133
-
- Association for Retarded Citizens of the U.S.
- P.O. Box 6109
- Arlington, TX 76005
- (817) 640-0204
- (800) 433-5252
-
- Mental Retardation Association of America
- 211 East 300 South, Suite 212
- Salt Lake City, UT 84111
- (801) 328-1575
-
- In Touch
- 10 Norman Road
- Sale, Cheshire
- M33 3DF
- Hants, England
-
- For information on genetics and genetic counseling referrals, please
- contact:
-
- 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
-
- SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th ed., Kenneth L.
- Jones, M.D., W.B. Saunders, Co. 1988. Pp. 16-9.
-
-