While normal people have 46 chromosomes, people with Turner syndrome usually have 45 chromosomes.
Turner syndrome is a genetic condition that only affects females. Normally, females have two X chromosomes (XX). However, in people with Turner syndrome, one X chromosome is either completely or partially missing or defective.
In about half of all cases of Turner syndrome, cells have only one X chromosome (a karyotype of 45,X). Others have a condition called mosaicism. In this, some cells may have 46 chromosomes (XX) and some cells may have 45 chromosomes (X). Therefore, the number of chromosomes may vary in people with mosaicism.
In short, people with Turner syndrome usually have 45 chromosomes, but this may be different in people with mosaicism.
