Triploidy is the presence of 69 chromosomes instead of the normal diploid number of 46 and can occur in a complete form or in a mixoploid state in which there are populations of diploid and triploid cells in the same individual. The extra haploid set can be of paternal or maternal origin. Triploidy is one of the most common chromosome aberrations seen in 1-2% of all recognized pregnancies and can lead to partial mole which can in turn lead to serious complications for the mother and fetus. Given the high incidence of chromosome abnormalities including triploidy and its impact on individuals with chromosomally abnormal pregnancies, a greater understanding of their etiology has a potential to contribute greatly to public health by enhancing the management and possible future prevention. Though complete triploidy is not compatible with postnatal survival, mixoploid individuals are capable of surviving into adulthood. Both syndromes have a broad phenotypic spectrum though it is generally less severe in mixoploids. Though much has been learned in the nearly half century since the first case report of diploid/triploid mixoploidy was published, many questions still remain. A major issue is a large between study difference in the ratio of diandric to digynic triploidy and the prevalence of partial hydatidiform mole. Additionally, there is a clear parent-of-origin effect on fetal and placental morphology as well as developmental age that is believed to be related to genomic imprinting. The goals of this paper include summarizing the current body of knowledge on triploidy and diploid/triploid mixoploidy, examining the remaining questions, and a side-by-side comparison of the two syndromes. An exhaustive literature search was undertaken which produced many case reports of triploidy and diploid/triploid mixoploidy as well as studies on the mechanisms leading to triploidy, phenotypic characteristics, and the characteristics of triploid cells. It appears that the complex pattern surrounding parental origin of the extra haploid set of chromosomes may have contributed to between study ascertainment bias. More complex studies with careful attention to detail must be undertaken to fully understand the etiology and pathophysiology of triploidy.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-07292009-143332 |
| Date | 29 September 2009 |
| Creators | Carson, Jason Christopher |
| Contributors | Urvashi Surti, Susanne Gollin, Eleanor Feingold |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-07292009-143332/ |
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