Turner's Syndrome Bibliography
Turner's Syndrome Questions

Turner’s Syndrome
By: Nicolette S., Maddie W., Emily N., and Teresa H.




How is Tuner’s Syndrome inherited?

Tuner’s Syndrome is the effect of what happens when a woman has only one X chromosome instead of two, or their second X chromosome has been altered.


Most cases of Turner’s syndrome are not inherited, in that the disorder does not typically run in families. Instead doctors say it is a random event during the formation of a woman or man’s reproductive cells.


The way a person gets Turner’s syndrome is when your mother or father made their reproductive cells, non-disjunction (the failure of chromosome pairs to separate during cell division) occurred.


Another type of this genetic disorder is Mosaic Turner syndrome. This occurs when some cells in a woman’s body have the regular XX chromosomes, while some cells only have one X. · This occurs during early fetal development.





Interesting Facts about Turner’s syndrome:

Turner’s syndrome affects about 60,000 families in the United States


One in every 2000-2500 babies are born with Tuner’s syndrome


75-80% of cases get the single X chromosome from the mother, while the father is one that does not pass on his sex chromosome


Tuner’s Syndrome is named for Dr. Henry Turner, who officially described the disorder in his book, in 1939


Women can live with only one X chromosome, but if men were missing their chromosome they would not have essential genes for life. The Y chromosome does not have many essential genes.


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What Type of Mutation causes this Disorder?

  • Definition: "an abnormal congenital condition resulting from a defect on or absence of the second sex chromosome, characterized by retarded growth of the gonads."

  • Turner Syndrome is listed as a "rare disease." Turner syndrome affects more than 200,000 women in the U.S population. Turner syndrome occurs when females inherit only one X chromosome- their genotype is XO. If they survive birth, these girls have abnormal growth. Girls with Turner syndrome are usually diagnosed either at birth or around the time they might be expected to go through puberty. In women who have who have Turner Syndrome, their ovaries don't develop normally and they do not ovulate.


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There are three types of Turner Syndrome. Three types of chromosomal abnormalities that can occur during cell division cause these three types of Turner Syndrome.

The first type of Turner Syndrome is Monosomy or Classic Turner Syndrome. This is the most common type of Turner's Syndrome and it affects approximately 50% of all Turner Syndrome cases. Females with this type of Turner syndrome show more of a physical features that are caused by this syndrome. Monosomy is the result of a missing X chromosome from the 23rd pair of chromosomes in every cell.

The second type of Turner's syndrome is called Mosaicism. Mosaics make up about 30-40% of all cases. This type of syndrome tends to show the least physical features and medical conditions. Females with Mosaic Turner syndrome will have many cells with the normal 46 chromosomes, but some will only have 45 chromosomes, or one slightly altered 46th chromosome. Thought 20% of these females will mentrate naturally, they may experience early menopause beginning in their late 20's or early 30's. Some females with Mosaic Syndrome may become pregnant and deliver perfectly healthy babies, although it is not very common.

The last type of Turner Syndrome is called Ischromosome. It occurs in 12-20% of cases. This type of Turner Syndrome is a result from the total or partial loss of the arm of the 46th chromosome. This happens when the chromosome divides latitudinally rather than longitudinally, which causes the chromosomal arms to tear. Just like Monosomy Turner Syndrome,called a karyotype.

For example, if a new-born girl shows signs of the condition, a doctor will order a special blood test. The test counts the number of chromosomes and is able to identify any abnormality, abnormally shaped, or any missing pieces. Sometimes there are no obvious signs that a girl is has Turner's Syndrome, and the condition is not diagnosed until she reaches puberty. If the karyotype blood test reveals that a girl has Turner's Syndrome, the doctor may take additional test to check for kidney, heart, diabetes, or hearing problems. In some conditions, Turner's Syndrome causes mental retardation. the physical and medical features are the same.






Characteristics:


The characteristics of Turner ’s syndrome can become apparent at birth and during infancy. They include:

  • a wide/webbed neck
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  • a small jaw
  • low set ears
  • a low hairline at the back of the head, drooping eyelids
  • a broad chest with widely spaced nipples
  • short hands, arms that turn outward at the elbows, fingernails turned upward
  • being slightly smaller than average at birth
  • swelled hands and feet at birth
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  • having delayed growth.

In some individuals the characteristics of Turner’s syndrome don’t become apparent until they become older or reach puberty. The symptoms that occur in adolescents and older women include:
· no growth spurts
· a short height
· learning disabilities (often in subjects involving math)
· difficulty understanding other’s emotions and feelings
· not going through normal sexual changes that usually occur during puberty (due to ovarian failure that could have occurred in which little to no estrogen or other hormones are produced)
· a non-existent menstrual cycle (not due to pregnancy)

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Treatments:


  • If caught early in life the first that would be started would be a weekly measured dossage of growth hormones called somatropin
    • used to increase height

    • should be started right when the disease is apparent(or by age of 4)


  • Ovarian hormone therapy
    • since mostly found in women once puberty starts(ages range from 12 to 15) patients are started on hormone therapy so that normal development of sexual parts can take place

    • helps to start puberty


  • Hormone replacement therapy
    • reduces chances of obtaining ovarian failure, osteoporosis,diabetes, and heart failure

    • also helps high blood pressure due to the size of the aorta or a kidney abnormality


  • Assisted reproduction
    • 50% of women who go through assisted reproduction have been reported to have become pregnant
      • This doesn't mean that the pregnancy is a sure deal. These women are still at a high risk of having a miscarriage, having twins, or their child being born with chromosomal abnormalities.