Search results
Results from the WOW.Com Content Network
Turner syndrome (TS), commonly known as 45,X, or 45,XO, [note 1] is a chromosomal disorder in which cells have only one X chromosome or are partially missing an X chromosome (sex chromosome monosomy) leading to the complete or partial deletion of the pseudoautosomal regions (PAR1, PAR2) in the affected X chromosome.
Trisomy X is a relatively common genetic disorder, occurring in around 1 in 1,000 female births. Due to its subtle effects, at most 10% of cases are diagnosed during their lifetime. [ 45 ] Large cytogenetic studies in Denmark find a diagnosed prevalence of 6 in 100,000 females, around 7% of the actual number of girls and women with trisomy X ...
In 45,X/46,XY, most or all of the Y chromosome is lost in one of the newly created cells. All the cells then made from this cell will lack the Y chromosome. All the cells created from the cells that have not lost the Y chromosome will be XY. [11] The 46,XY cells will continue to multiply at the same time as the 45,X cells multiply.
Most spiders have a variation of the XO system in which males have two different X chromosomes (X 1 X 2 O), while females have a pair of X 1 chromosomes and a pair of X 2 chromosomes (X 1 X 1 X 2 X 2). [1] Some spiders have more complex systems involving as many as 13 different X chromosomes. [1] Some Drosophila species have XO males. [10]
Sex chromosome anomalies belong to a group of genetic conditions that are caused or affected by the loss, damage or addition of one or both sex chromosomes (also called gonosomes). In humans this may refer to: 45, X, also known as Turner syndrome; 45,X/46,XY mosaicism, also known as X0/XY mosaicism and mixed gonadal dysgenesis; 46, XX/XY
46,XX/46,XY chimeric or mosaic is associated with a wide spectrum of different physical presentations, with cases ranging from having a completely normal male or female phenotype [7] [8] [9] to some cases having ovotesticular syndrome. Due to this variation, genetic testing is the only way to reliably make a diagnosis. [11] [12] [13] [6]
Klinefelter syndrome is not an inherited condition. The extra X chromosome comes from the mother in approximately 50% of the cases. Maternal age is the only known risk factor. Women at 40 years have a four-times-higher risk of a child with Klinefelter syndrome than women aged 24 years. [14] [34] [35]
Klinefelter syndrome can also result from an extra X chromosome in only some of the body's cells. These cases are called mosaic 46,XY/47,XXY. Trisomy X. This syndrome results from an extra copy of the X chromosome in each of a female's cells. Females with trisomy X have three X chromosomes, for a total of 47 chromosomes per cell.