<u><em>Trisomy X, also known as triple X syndrome and 47,XXX, is characterized by the presence of an extra X chromosome in each cell of a female. Those affected are often taller than average.</em></u>
<u><em>Klinefelter syndrome (sometimes called Klinefelter's, KS or XXY) is where boys and men are born with an extra X chromosome. Chromosomes are packages of genes found in every cell in the body. There are 2 types of chromosome, called the sex chromosomes, that determine the genetic sex of a baby.</em></u>
