45x-2. 47xy, +16-trisomy 16 is a chromosomal abnormality in which there are 3 copies of chromosome 16 rather than two. it is the most common trisomy leading to miscarriage and the second most common chromosomal cause of it, closely following x-chromosome monosomy. like most chromosomal abnormalities, trisomy 16 usually causes miscarriage in the first trimester of pregnancy.
it is not possible for a child to be born alive with an extra copy of this chromosome present in all cells (called full trisomy 16). it is possible for a child to be born alive with the mosaic form
despite the excellent postnatal prognosis, 99% of turner-syndrome conceptions are thought to end in spontaneous abortion or stillbirth, and as many as 15% of all spontaneous abortions have the x,o karyotype