“This type of Down syndrome accounts for less than 4% of all cases.” Mosaic Down syndrome: Among Down Syndrome patients, less than 1% have Mosaic Down syndrome.

“In the most common type of Down syndrome, there are 47 chromosomes, with the extra one being chromosome 21 — so the patient has three No. 21 chromosomes in all the cells of their body.

Although there is a wide range in how Down syndrome may present in different patients, it can sometimes be a devastating disease. There are no treatments for the condition. This work has shown that it ...