Mosaic Down Syndrome is due to the presence of two different groups of cells in one individual. One group of cells contains the 46 chromosome and the other group of cells contains an extra copy of the chromosome #21, making 47 cells total for this group.
Pronunciation: “Moe” “zay” “ick” “down” “sin” “drome”
About 2-3% of the time, Down syndrome is caused by two separate cell lines in one individual. One cell line contains the typical number of chromosomes and one cell line contains an extra number 21 chromosome.