Sex Chromosome Abnormalities
Examples of Sex Chromosome Abnormalities

Sex chromosome abnormalities all stem from an incorrect number of X or Y chromosomes.

Here are some examples:

  • About 1 in 1,000 males is born with an extra Y chromosome, known as Klinefelter's syndrome.
  • About 1 in 85,000 males has additional X chromosomes. These syndromes include XXXY syndrome, XX male syndrome and XXYY syndrome.
  • Women may have only one X (Turner Syndrome) or up to five of them.

[source: Merck]

Sex chromosome abnormalities occur when there's a problem during egg or sperm production. In people, typical eggs and sperm cells have 23 chromosomes. Sex chromosome abnormalities occur when an egg or sperm has too few or too many. Regardless of which cell has the wrong number, the resulting embryo has more or fewer than 46 chromosomes total, leading to a range of physical and developmental problems. Sometimes these syndromes are basically asymptomatic, but others can have severe effects including developmental disabilities, emotional problems, sterility, organ problems and physical abnormalities.

Sex chromosome abnormalities may be detected during pregnancy via chorionic villi sampling (CVS) or amniocentesis. Depending on the abnormality, some of these pregnancies may result in miscarriage or stillbirths. Girls born with Turner syndrome have distinctive physical characteristics, but other abnormalities must be diagnosed via genetic testing. Treatment of these abnormalities may include estrogen or testosterone replacement therapy, growth hormone therapy, surgery to correct physical defects, and intervention to assist with behavioral and learning difficulties.

We'll look at another biological unusual sexual condition next.