There are three different types of Down syndrome but all give rise to similar physical and behavioural features. In about 95% of cases, babies are born with a whole and separate extra copy of ...

While Emma has Down syndrome — specifically a rare type called Mosaic Down syndrome — some people don’t believe it. ... is “attached” to a different chromosome.

“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.

DSCAM gene triplication causes excessive GABAergic synapses in the neocortex in Down syndrome mouse models. PLOS Biology , 2023; 21 (4): e3002078 DOI: 10.1371/journal.pbio.3002078 Cite This Page : ...

Down syndrome, also known as trisomy 21, is caused by an extra copy of chromosome 21 and is associated with differences in neurodevelopment and a distinct clinical risk profile.