Definition
Turner syndrome occurs when one of the X chromosomes (sex chromosomes) is
missing or partially missing. It only affects females and causes problems like short height, failure of the ovaries to develop and heart defects.
Causes
Turner syndrome is caused by chromosomal errors during fetal development and other developmental problems after birth. There are different genetic alterations of turner syndrome:
- Monosomy, which results in every cell in the body having only one X chromosome.
- Mosaicism, which results in some cells in the body having two complete copies of the X chromosome while other cells have only one copy of the X chromosome.
- X chromosome abnormalities which occur in the sperm or egg with all cells or in cell division in early fetal development with only some cells having one complete and one altered copy.
- Y chromosome material which increases the risk of developing a type of cancer called gonadoblastoma because of the presence of Y chromosome material in some cells.
