A type of trisomy, known as trisomy X or 47 XXX, is an extremely rare genetic anomaly which only affects women. Instead of the normal combination of X chromosomes, the female DNA will contain an extra X chromosome. Normally, the female DNA contains two X chromosomes, though women affected by trisomy X will have three.
Trisomy X is rarely fatal (unless it affects a female child immediately after birth), though the symptoms can be life-changing. Changes in mental development, motor skills and appearance can be the most common, along with delayed puberty, and epicanthal folds. Among adult women, infertility can be common as well. Currently, there is no cure, though most woman affected by trisomy X can still live a relatively normal life.