2006-07-12 13:58:20 · 9 answers · asked by princess 3 in Health ➔ Other - Health
Down syndrome is due to having an extra chromosome and is called Trisomy 21 because while "normal" people have two copies of chromosome 21 (one from dad, one from mom), the people with this syndrome have three copies of it, and the extra genes cause the symptoms. Extra copies of most other chromosomes will result in the fetus dying.
2006-07-12 14:00:48 · answer #1 · answered by mrchinlersir 5 · 0⤊ 0⤋
Down's Syndrome is caused during DNA translation in a new embryo. DNA often makes errors when copying itself (mutations, etc) however sometimes the error is as big as an extra chromosome being copied, and in this case it would be chromosome 21. I gave a very vague description of why, but the website below will tell you everything you need to know. Hope this could help you out!
2006-07-12 14:08:03 · answer #2 · answered by Anonymous · 0⤊ 0⤋
downs syndrome = trisomy 21 = three number 21 chromosones. (there are only suppose to be two) it can happen from conception, or somewhere down the line in the cellular division of the fetus. a true trisomy is from conception, a mosaic trisomy happens somewhere down the line one of the cells divides improperly (for unknown reasons). every division after that one copies and divides with the extra chromosone present. there can be different degrees of abnormality depending on how "formed" the fetus is when the mutation shows up in the mosaic trisomy child.
2006-07-12 14:27:47 · answer #3 · answered by Anonymous · 0⤊ 0⤋
your question is confusing -- down sydnrome is not "formed" it arise from a genetic abnormality of chromosome 21 -- this is due to a mutation in utero. Can be detected during a woman's pregnancy in the first trimerster with a triple screen (which measures 3 hormone levels in the mom's blood), as well as an ultrasound and other more invasive studies such as CVS. a woman's chance of having a baby with Down syndrome increases as she ages. Down syndrome patient have characteristic facies, as well as heart defects, increased risk of leukemia, early onset Alzheimer's dementia, mental retardation, as well as a number of other abnormalities.
2006-07-12 14:07:25 · answer #4 · answered by cloudybamboo2002 1 · 0⤊ 0⤋
Malfunction.
(Mutation.)
2006-07-12 14:01:20 · answer #5 · answered by NA A 5 · 0⤊ 0⤋
Actually, it's an extra chromosome.
2006-07-12 14:01:57 · answer #6 · answered by Chark Finn 2 · 0⤊ 0⤋
It was that Trisomy 21, they dont have that.
2006-07-12 14:01:46 · answer #7 · answered by orkid 1 · 0⤊ 0⤋
It is when there is one too few chromosomes
2006-07-12 14:01:32 · answer #8 · answered by Anonymous · 0⤊ 0⤋
It is a extra chromosone .I DON'T know if it is X or Y.
2006-07-12 14:06:38 · answer #9 · answered by ARLENE H 4 · 0⤊ 0⤋