In mosaic trisomy 8, there is an extra copy of the 8th chromosome in some of your cells. It's not a common condition, occurring in only about 1 baby in 25,000 to 50,000 live births. It shows up ...

Trisomy 13, or Patau syndrome, occurs when a fetus has an extra chromosome 13. This rare condition can cause developmental effects and may have a poor outlook.

There was a trend toward patients with trisomy 8 being older (P=.08), having higher bone marrow CD3+/CD38- cell burden (P=.05), and a distinct immunophenotype, compared to patients without trisomy 8.

Babies born with mosaic Down syndrome may have similar features and health issues as those born with trisomy 21 Down syndrome. Overall, though, they may have fewer of these characteristics.