Down Syndrome Screening
Many women over 40 want their pregnancy to be screened for Down Syndrome but they're afraid because there is a slight risk of miscarriage with the procedure.See: getpregnantover40.com for more articles on having a healthy pregnancy over 40
The article below talks about a new blood test which can also screen for Down Syndrome but does not have the miscarriage risk of an amnocentisis. Read more:
A child with Down's inherits an extra copy of chromosome 21 from their mother or father. Now two research teams have devised a simple blood test – that they say carries no risk of miscarriage – to detect this extra copy by analysing fetal genetic material shed into a mother's blood.
Though the findings are still preliminary, Dennis Lo of the Chinese University in Hong Kong, who first proposed fetal DNA testing in 1997, is optimistic that far fewer women will need invasive tests for Down's. "This problem really appears to be solvable," he says.
Geographical limits
Lo's method, developed in 2007, is now being commercialised by Sequenom of San Diego, California.
The approach focuses on a stretch of chromosome 21 that is only expressed in fetuses. Sequenom detects this RNA and determines which parent it comes from by identifying differences between the individuals in single-letter variations called single nucleotide polymorphisms (SNPs).
from:
(www.newscientist.com)
