Four cases of D 1-trisomy syndrome have been described by the Wisconsin group, 1–3 as have 6 cases of 18-trisomy syndrome. 4,5 One case reported by Edwards et al. 6 resembles the latter syndrome ...

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.

Among high-risk pregnancies, sequencing circulating cell–free DNA detects nearly all cases of Down syndrome, trisomy 18, and trisomy 13, at a low false-positive rate.

Trisomy 18 is the second-most common type of trisomy syndrome, after trisomy 21 (Down syndrome). About 1 in every 5,000 babies are born with trisomy 18, and most are female.

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.

Trisomy 18, or Edwards syndrome, occurs when a fetus has an extra chromosome 18. This rare condition can affect development and may have a poor outlook.