Turner syndrome (TS) is a complex phenotype associated with complete or partial monosomy of the X chromosome, usually the result of a sporadic chromosomal nondisjunction. TS is one of the most common sex chromosome abnormalities, affecting approximately 1 in 2,000 live born females [1–3].
Is Turner syndrome meiotic nondisjunction?
Nondisjunction may occur during meiosis I or meiosis II. Aneuploidy often results in serious problems such as Turner syndrome, a monosomy in which females may contain all or part of an X chromosome. Monosomy for autosomes is usually lethal in humans and other animals.
What type of mutation causes Turner syndrome?
Turner syndrome is caused by partial or complete loss (monosomy) of the second sex chromosome. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual and they come in pairs.
What is the chromosome combination for Turner syndrome?
Turner syndrome (TS), also known as 45,X, or 45,X0, is a genetic condition in which a female is partially or completely missing an X chromosome. Signs and symptoms vary among those affected.
How is Turner syndrome caused?
Turner syndrome occurs when part or all of an X chromosome is missing from most or all of the cells in a girl’s body. A girl normally receives one X chromosome from each parent. The error that leads to the missing chromosome appears to happen during the formation of the egg or sperm.
What causes nondisjunction?
Nondisjunction occurs when chromosomes fail to segregate during meiosis; when this happens, gametes with an abnormal number of chromosomes are produced.
What is Parsonage Turner Syndrome?
General Discussion. Summary. Parsonage-Turner syndrome (PTS) is an uncommon neurological disorder characterized by rapid onset of severe pain in the shoulder and arm. This acute phase may last for a few hours to a few weeks and is followed by wasting and weakness of the muscles (amyotrophy) in the affected areas.
Is Turner syndrome genetic or chromosomal?
Turner syndrome is a chromosomal condition that affects development in females. The most common feature of Turner syndrome is short stature, which becomes evident by about age 5. An early loss of ovarian function (ovarian hypofunction or premature ovarian failure) is also very common.
Is Turner syndrome a genetic mutation?
Turner syndrome is a genetic disorder affecting girls and women. The cause of Turner syndrome is a completely or partially missing X chromosome. Turner syndrome symptoms include short stature and lack of breast development and periods. Treatment for Turner syndrome may include hormone therapy.
How many chromosomes does Turner syndrome have?
To diagnose Turner syndrome, doctors use a special blood test that looks at chromosomes, called a karyotype test (chromosomal analysis). Results that indicate TS show only one X chromosome instead of two X chromosomes, with a total of 45 chromosomes instead of the usual 46.
Which observations would indicate findings found in a child with Turner syndrome?
Signs of Turner syndrome at birth or during infancy may include: Wide or weblike neck. Low-set ears. Broad chest with widely spaced nipples.
Which characteristic is commonly associated with Turner syndrome?
Turner syndrome can affect: Appearance. Features of Turner syndrome may include a short neck with a webbed appearance, low hairline at the back of the neck, low-set ears, hands and feet that are swollen or puffy at birth, and soft nails that turn upward. Stature.
Is Turner syndrome caused by aneuploidy?
Sex chromosome aneuploidies, in mosaic and nonmosaic forms, result in recognizable syndromes such as Turner syndrome (45,X and associated karyotypes) and Klinefelter syndrome (47,XXY). Sex chromosome DSD are defined by aneuploidy of the sex chromosomes, X and Y.
Why does Turner syndrome only occur in females?
In Turner syndrome, cells are missing all or part of an X chromosome. The condition only occurs in females. Most commonly, a female with Turner syndrome has only 1 X chromosome. Others may have 2 X chromosomes, but one of them is incomplete.