Down’s,+Turner’s,+and+Klinefelter’s+Syndrome

Down's Syndrome is the results of a trisomy (extra copy) of chromosome 21. It causes limited mental abilities (retardation), distinctly different facial characteristics, and heart defects.

Klinefelter's Syndrome is the result of an XXY genotype. This means that the person has two X chromosomes and one Y chromosome. These males often are tall, exually underdeveloped, and may have a slight mental disability.

Turner's Syndrome is the result of an XO genotype. The person has just one X chromosome, and no second chromosome. These females are usually short, sexually underdeveloped, and infertile.