Trisomy 9
| Trisomy 9 | |
|---|---|
 | |
| Chromosome 9 | |
| Specialty | Medical genetics |
| Causes | three copies ofChromosome 9 |
| Prognosis | Invariably fatal none treatment |
Fulltrisomy 9is a rare and fatalchromosomal disordercaused by having three copies (trisomy) ofchromosome number 9.It can be a viable condition if trisomy affects only part of the cells of the body (mosaicism) or in cases of partial trisomy (trisomy 9p) in which cells have a normal set of two entire chromosomes 9 plus part of a third copy, usually of the short arm of the chromosome (arm p).
Presentation
[edit]Symptoms vary, but usually result indysmorphismsin theskull,nervous systemproblems, and developmental delay. Dysmorphisms in theheart,kidneys,andmusculoskeletalsystem may also occur. An infant with complete trisomy 9 surviving 20 days after birth showed clinical features including a small face, widefontanelle,prominentocciput,micrognathia,low set ears, upslantingpalpebral fissures,high-arched palate,shortsternum,overlapping fingers, limited hip abduction,rocker bottom feet,heart murmursand a webbed neck.[1]
Trisomy 9p is one of the most frequent autosomal anomalies compatible with long survival rate. A study of five cases showed an association withCoffin–Siris syndrome,as well as a wide gap between the first and second toes in all five, while three had brain malformations including dilatedventricleswith hypogenesis of thecorpus callosumandDandy–Walker malformation.[2]
Diagnosis
[edit]Trisomy 9 can bedetected prenatallywithchorionic villus samplingandcordocentesis,and can be suggested byobstetric ultrasonography.[citation needed]
Because trisomy 9 may appear withmosaicism,it is suggested that doctors take samples from multiple tissues whenkaryotypingfor diagnosis.[3]
References
[edit]- ^Kannan, T. P.; Hemlatha, S.; Ankathil, R.; Zilfalil, B. A. (2009). "Clinical manifestations in trisomy 9".The Indian Journal of Pediatrics.76(7): 745–6.doi:10.1007/s12098-009-0158-2.PMID19475342.S2CID207385217.
- ^Temtamy, SA; Kamel, AK; Ismail, S; Helmy, NA; Aglan, MS; El Gammal, M; El Ruby, M; Mohamed, AM (2007). "Phenotypic and cytogenetic spectrum of 9p trisomy".Genetic Counseling.18(1): 29–48.PMID17515299.
- ^Stipoljev, F.; Kos, M.; Kos, M.; Miskovi, B.; Matijevic, R.; Hafner, T.; Kurjak, A. (2003). "Antenatal detection of mosaic trisomy 9 by ultrasound: A case report and literature review".The Journal of Maternal-Fetal & Neonatal Medicine.14(1): 65–9.doi:10.1080/jmf.14.1.65.69.PMID14563095.S2CID24028391.
External links
[edit]- NORD - National Organization for Rare Disorders, Inc.Chromosome 9, Trisomy 9p (Multiple Variants)
- NORD - National Organization for Rare Disorders, Inc.Chromosome 9, Trisomy Mosaic