Sex Chromosome Aneuploidies

Trisomy X

Triple X syndrome, also called trisomy X, is a genetic disorder that affects about 1 in 1,000 females. Females normally have two X chromosomes in all cells — one X chromosome from each parent. In triple X syndrome, a female has three X chromosomes. Many girls and women with triple X syndrome have no symptoms or only mild symptoms. In other cases, symptoms may be more pronounced — possibly including developmental delays and learning disabilities.

Monosomy X (Turner Syndrome)

A girl inherits one X chromosome from each parent. If a girl has Turner syndrome, one copy of the X chromosome is missing or significantly changed. The missing or altered X chromosome of Turner syndrome causes errors during fetal development and other developmental problems after birth — short stature, ovarian failure and learning disabilities.