Jonathon Langdon Down was the first physician to identify Down Syndrome, which causes mild to severe mental and physical impairments. It is a genetic condition caused when cells in a embryo divide improperly and create a third chromosome in the 21st pair. Down Syndrome is also called Trisomy 21. It appears in one out of every 800 live births.
Types
Down Syndrome can either be complete, meaning every 21st chromosome in the body has an extra chromosome, or it can be mosaic, where only some of the chromosomes have an additional chromosome in the 21st pair.
Types
The rarest type of Down Syndrome is translocation Trisomy 21 and occurs when a piece of one of the 21st chromosome attaches to another chromosome, or translocates.
Time Frame
Women under 30 have less than a one in 1,000 chance of conceiving a child with Down Syndrome, but the odds increase as women age. By 40, the ratio is one in 105 and rises all the way to one in 12 by the age of 49.
Considerations
While women with advanced maternal age (greater than 35) are more likely to conceive a baby with Down Syndrome, more babies with Down Syndrome are born to younger women, because more young women than older women have babies.
Prevention/Solution
As of 2009, there is no prevention for Down Syndrome but for women at risk from age or genetic factors, prenatal tests like chorionic villi sampling (CVS), percutaneous umbilical blood sampling (PUBS) or amniocentesis are available between 10 and 18 weeks of gestation to determine if a child has Down Syndrome.
Tags: Down Syndrome, with Down Syndrome, 21st chromosome, 21st pair, chromosome 21st, chromosome 21st pair, with Down