Trisomy 9
| Trisomy 9 | |
|---|---|
| Other names | Skull dysmorphisms, nervous system problems, developmental delay |
| chromosome 9 | |
| Specialty | Medical genetics |
| Complications | Coffin–Siris syndrome |
| Usual onset | At birth |
| Types | Complete, mosaic, partial |
| Causes | Three copies of Chromosome 9 |
| Diagnostic method | Karyotype |
| Prognosis | Invariably fatal, no known effective treatment |
Full trisomy 9 is a rare and fatal chromosomal disorder caused by having three copies (trisomy) of chromosome 9. It can be a viable condition if the trisomic component affects only part of the cells of the body (mosaicism) or in cases of partial trisomy of the short arm (trisomy 9p) in which cells have a normal set of two entire chromosomes 9 plus part of a third copy of the short arm ("p") of the chromosome.