Support Organization For Trisomy Awareness
All humans have 46 chromosomes arranged in 23 pairs. We get 23 chromosomes from mom and 23 from dad. The word trisomy refers to a condition in which there is a third copy (tri-) of a specific chromosome (-somy). Trisomy is a condition that occurs before conception (either the sperm or the egg has an extra chromosome) and there are no current therapies that can reverse or treat the condition once fertilization has occurred.
There are a variety of tests and procedures that can be used to diagnose trisomy beginning early in a pregnancy. The great majority of pregnancies affected by a trisomy will result in early (usually first trimester) miscarriage, but many affected pregnancies do result in a live birth. The most common trisomies are:
Trisomy 21 (Down Syndrome): This is the most common trisomy seen in live births. The older the mom at the time of conception, the higher the risk. People born with trisomy 21 can survive well into their sixties, though with varying degrees of intellectual and physical, and anatomical anomalies.
Trisomy 16 is the most common trisomy though it invariably ends in miscarriage.
Trisomy 18 (Edward’s Syndrome): Most babies born with trisomy 18 have physical defects involving almost every organ system resulting, unfortunately, in a very low survival rate beyond the first year of life.
Trisomy 13 (Patau’s Syndrome): Much like trisomy 18, these infants have a host of physical anomalies and malformations that almost always result in death before the end of the first year of life.
Trisomy 23 (Sex Chromosome Abnormalities): Normal females have XX chromosomes; normal males XY. Males with XXY chromosomes (Klinefelter’s syndrome) CAN exhibit sterility, muscle weakness, tall stature, less body hair, smaller genitals and breast growth. Men with XYY Syndrome also have very subtle characteristics (tall stature, increased acne and a mild reduction in intelligence). Women with triple XXX chromosomes appear and generally function normally and often times the diagnosis is never made.
Why is trisomy awareness important? This gets to the heart of a discussion that every expectant couple has to have and one that I encourage all of my expectant parents to have very early on in the pregnancy. While there is nothing that can be done to prevent or treat the various trisomies, the information that testing provides can be invaluable.