If you have Turner Syndrome, or are a sibling, friend or parent of a girl with Turner Syndrome, you may wonder…what exactly causes someone to be born with Turner Syndrome?
Turner Syndrome is a disorder involving the chromosomes. A “normal” girl has a 46,XX karyotype and a normal boy has a 46,XY karyotype. However, an estimated 1 in every 2000 or so girls is born with a 45,XO karyotype…meaning she is missing a second X chromosome. This is caused by an error during conception.
Many, if not most, girls with Turner Syndrome are actually what is called “Mosaic”. This means that they have a few cells with a normal 46,XX or even sometimes a normal 46,XY karyotype. Unfortunately, Mosaicism is not always detected by Karyotype tests.