In general it can be said that many people with Mosaic Down Syndrome have fewer symptoms, but this isn’t always the case. Though a medically interesting variant, this type of Down syndrome is sometimes just as likely as total Trisomy 21 to have the following symptoms: Impaired cognition, ...
I too assumed that fewer presence of three 21st chromosomes in cells would mean that individuals with Mosaic Down Syndrome would have less symptoms. It's kind of interesting why that isn't the case. I guess a child with Mosaic Down Syndrome needs the help and attention that children with Do...