Editing Down syndrome (section)

=== Mosaic Down syndrome ===
[[Mosaic (genetics)|Mosaic]] Down syndrome is diagnosed when there is a mixture of two types of cells: some cells have three copies of chromosome 21 but some cells have the typical two copies of chromosome 21.<ref name="CDC"/> This type is the least common form of Down syndrome and accounts for only about 1% of all cases.<ref name=":0">{{Cite web |title=What is Down Syndrome? {{!}} National Down Syndrome Society |url=https://www.ndss.org/about-down-syndrome/down-syndrome/ |access-date=2022-03-24 |website=NDSS |language=en-US}}</ref> Children with mosaic Down syndrome may have the same features as other children with Down syndrome. However, they may have fewer characteristics of the condition due to the presence of some (or many) cells with a typical number of chromosomes.<ref name="CDC">{{Cite web |date=2021-04-06 |title=Facts about Down Syndrome {{!}} CDC |url=https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html |access-date=2023-03-31 |website=Centers for Disease Control and Prevention |language=en-us}}</ref>