2. What is Down syndrome? Down syndrome is a genetic condition in which a person has 47 chromosomes instead of the usual 46. This disorder causes mental retardation and other problems. Down syndrome ranges in severity, so developmental problems may range from mild to serious.
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5. With Mosaic Down syndrome some cells have an extra copy of chromosome 21, but not all.
6. Mosaic Down syndrome is caused by abnormal cell division after fertilization.
7. occurs when part of a chromosome 21becomes attached onto another chromosome, before or at conception.
8. Children with Translocation have the usual 2 copies of chromosome 21, but have additional material from chromosome 21 stuck to the translocated chromosome. MOST cases of Down syndrome are NOT inherited.
19. Age 45 = 1 in 30 chance Women who already have a child with Down syndrome typically have a 1 % chance of having another child with Down syndrome. Parents who are carriers of the translocation for Down syndrome can pass the genetic translocation onto their children.
