Down Syndrome

Q: My baby has mosaic Down syndrome. What does that mean? A: Children with mosaic Down syndrome have two distinct cell groupings. In some cells there is a total of 46 chromosomes, which is the “typical” group. In other cells there is an extra copy of the chromosome #21, making 47 cells total for this group. Q: How does mosaic Down syndrome happen? A: Ordinarily, when an egg and a sperm are joined at conception, a single cell …

…The number of blood cells containing 46 chromosomes may not accurately reflect the number of skin cells, heart cells, or brain cells with 46 chromosomes. Therefore, it is impossible to predict what affect, if any, the presence of these chromosomally normal cells will have on a child’s development. The parents of children with mosaic Down syndrome are like the parents of any other child. Your child’s strengths and weaknesses will only be revealed over time.