Medical Encyclopedia |
|
Other encyclopedia topics: | A-Ag Ah-Ap Aq-Az B-Bk Bl-Bz C-Cg Ch-Co Cp-Cz D-Di Dj-Dz E-Ep Eq-Ez F G H-Hf Hg-Hz I-In Io-Iz J K L-Ln Lo-Lz M-Mf Mg-Mz N O P-Pl Pm-Pz Q R S-Sh Si-Sp Sq-Sz T-Tn To-Tz U V W X Y Z 0-9 |
Contents of this page: | |
Alternative Names
Bonnevie-Ullrich syndrome; Gonadal dysgenesis; Monosomy XDefinition Return to top
Turner syndrome is a genetic condition in which a female does not have the usual pair of two X chromosomes.
Causes Return to top
Humans have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. Two of these chromosomes, the sex chromosomes, determine if you become a boy or a girl. Females normally have two of the same sex chromosomes, written as XX. Males have an X and a Y chromosome (written as XY).
In Turner syndrome, cells are missing all or part of an X chromosome. The condition only occurs in females. Most commonly, the female patient has only one X chromosome. Others may have two X chromosomes, but one of them is incomplete. Sometimes, a female has some cells with two X chromosomes, but other cells have only one.
Turner syndrome occurs in about 1 out of 2,000 live births.
Symptoms Return to top
Possible symptoms in young infants include:
A combination of the following symptoms may be seen in older females:
Exams and Tests Return to top
Turner syndrome can be diagnosed at any stage of life. It may be diagnosed before birth if chromosome analysis is done during prenatal testing.
The doctor will perform a physical exam and look for signs of underdevelopment. Infants with Turner syndrome often have swollen hands and feet.
The following tests may be performed:
Turner syndrome may also alter various estrogen levels in the blood and urine.
Treatment Return to top
Growth hormone may help a child with Turner syndrome grow taller. Estrogen replacement therapy is often started when the girl is 12 or 13 years old. This helps trigger the growth of breasts, pubic hair, and other sexual characteristics.
Women with Turner syndrome who wish to become pregnant may consider using a donor egg.
Support Groups Return to top
For additional information and resources, see:
Turner Syndrome Society -- www.turnersyndrome.org
Outlook (Prognosis) Return to top
Those with Turner syndrome can have a normal life when carefully monitored by their doctor.
Possible Complications Return to top
Prevention Return to top
There is no known way to prevent Turner syndrome.
Update Date: 9/26/2007 Updated by: Deirdre O’Reilly, MD, MPH, Neonatologist, Division of Newborn Medicine, Children’s Hospital Boston and Instructor in Pediatrics, Harvard Medical School, Boston, Massachusetts. Previously reviewed by Brian Kirmse, MD, Mount Sinai School of Medicine, Department of Human Genetics, New York, NY. Review provided by VeriMed Healthcare Network.
EDIZIONI DI PUBBLICO DOMINIO (HTML)
- Alighieri - La Divina Commedia
RISORSE DAL WEB:
Encyclopaedia Britannica 1911 - PDF
Project Gutenberg: DVD-ROM 2007
Wikipedia for Schools - ENGLISH
Wikipedia for Schools - FRENCH
Wikipedia for Schools - SPANISH