Timing of error. At conception, the embryo begin duplicating the chromosomes (chms) donated by egg & sperm to form the 23 chromosome pairs. If one x chm didn't make it, you will only have a turner pattern (45 chms xo). If a normal xx pattern starts but an x is lost after several divisions the mosaic is created by having one normal 46xx & another 45xo cell lines replicating throughput the body.
A little complex. Classic turner syndrome is a female who is missing 1 of the 2 x chromosomes, designated as 46x. A normal female has 2 x chromosomes (46xx). Most turner mosaics have a mix of normal cells and turner cells resulting in a milder form of turner syndrome. There are several variations however-- some with 1 normal and one abnormal x chromosomes and evan a male form with a normal x and an abnormal y.
Two cell lines. Regular turner syndrome arises when the drop out of one "x" sex chromosome occurs before or at conception, then all babies cells would have xo turner. When it drops out after conception, after the first, second or whatever cell division, a line of xo affects that cell line but normal xx are in the other cells. Mosaics have less turner specific abnormalities but effect varies on % of affected cells.
Partial. Turner syndrome occurs when a girl only has one x chromosome. Mosaic turner syndrome occurs when some of the cells in a girl have two x chromosomes and the rest have one x chromosome. Women with mosaic turner syndrome can have all of the same problems as women with turner syndrome, but the severity tends to be milder. Short stature, sterility, heart disease, and learning problems can all occur.
Variation of Theme. Most females have 2 x chromosomes as part of their genetic make-up in all cells. In classic ts females are born with 1 x chromosome in most or all cells. Patients who are mosaic are those who may be missing just part of an x or they could have some cells with 2 x's and others with only 1 x. There are other variations. Mosaic ts patients are usually not as severely affected as classic ts patients.
I have mosaic Turner syndrome and my karyotype is 45x. Since I don't have typical female chromosomes does this mean I am intersex?
Sexual identity. You are the gender you feel you are as genes only play a part of our sexual identity.
Not at all. It is impossible to say whether your ovaries are 45X or 46XX. The mosaicism, some tissues have many more of one than another. 45X females are typically female. Without growth hormone therapy they are under 5 feet tall. Most 45X females go through ovarian failure even before they have a chance to go through puberty, so they never menstruate. See http://www. Turnersyndrome. Org.