Most people have 46 chromosomes in each of their cells, and two of those 46 chromosomes are sex chromosomes. Most girls and women have two X sex chromosomes (so we say their chromosomal component is “46,XX”). Most boys and men have an X sex chromosome and a Y sex chromosome (“46,XY”).
Turner syndrome is a condition in which a person’s cells contain the chromosomal component 45,X. In other words, she has one X chromosome instead of two. (Sometimes this is written “45,X0.”)
Some people with Turner syndrome actually have sex chromosome mosaicism, meaning that not all their cells have the same component of chromosomes. This is called “mosaicism” because it is sort of like the body is made up of a varied set of colored tiles, rather than a single-colored set of tiles. When a person has more than one component of sex chromosomes, the person is said to have “sex chromosome mosaicism.” Some people have 45,X in some of their cells and 46,XX in others, or more rarely 45,X with 46,XY.
The main support group for Turner syndrome is the Turner Syndrome Society. Click here for their website.
Posted in: Specific Conditions