There are three forms of Trisomy 9:
- Full Trisomy 9 is the most severe form in which every cell has three copies of chromosome 9. In most cases the developing embryo is not viable and the pregnancy will end in the first trimester by miscarriage. Some babies with full Trisomy 9 survive until birth, but only live for a short period of time.
- Partial Trisomy 9 involves an extra portion of chromosome 9 is included in each cell. You can get an idea of what that might look like here (scroll down to diagnosis). Life expectancy with this form of Trisomy 9 varies widely. This form is generally more rare than full and mosaic forms.
- Similar to Trisomy 8, Trisomy 9 often occurs in a mosaic form in which some, but not all, of an individual's cells have three copies of chromosome 9. Depending on the severity of medical challenges the life span of individuals with Mosaic Trisomy 9 can be shortened dramatically.
For more information on Trisomy 9, check out the following links: