| Research Abstract |
#1. Diagnosis and Management of IUGR
550 pregnant women treated in Nagasaki University Hospital were screened for their fetal growth by using ultra sonography and then intrauterine growth retardation (IUGR) were detected in this study. Also, CTG, ultrasonography and flow volume of uterine artery and umbilical artery were investigated to know the pathogenesis of IUGR. 17 unknown cases of IUGR were included in this study because they showed less than - 2SD degree of growth retardation and their pathogenesis of IUGR were still unknown.
#2. Sampling
This project had obtained a nagasaki university ethical committee's aprroval. Placenta tissues, mather's and father's blood samples were collected from above 17 unknown cases. Also, placenta tissues, mather's and father's blood samples from normal control were preserved for this study.
#3. screening of confined placental mosaicism (CPM)
Cytogenetic studies from fetal blood and placentas were done. Three of 17 cases had cytogenetic abnormalities in b
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oth fetal blood and placenta. Two of 17 cases had cytogenetic abnormalities only in placenta but not in fetal blood (confined placental mosaicism). Two cases of remaining 12 cases who had no cytogenetic abnormalities were diagnosed phenotypically as a Russell Silver Syndrome. Russell Silver Syndrome may be caused by a deficit of imprinted gene located on chromosome 7, suggesting chromosomal abnormalities such as uniparental disomy (UPD) would be happened in these cases who showed the phenotypes of Russell Silver Syndrome.
#4. Screening of UPD
The karyotype of CPM detected in this project were 47, XX, +22/46, XX and 47, XX, +7/46, XX. There was a possibility that IUGR detected in these two cases might be caused by UPD. Therefore, we choosed highly polymorphic microsatellite markers in Japanese, which were covering entire chromosome 22 and chromosome 7. By using these markers, we investigated if UPD was existing in these two cases with CPM or not. However, no UPD was detected in this study, suggesting that unknown severe IUGR was caused by rather placental deficiency due to mosaicism than UPD.
In this study, it is suggested that some of unknown severe IUGR (less than -2SD) may be caused by cytogenetic and/or genetic abnormalities. Cytogenetic and genetic screening against unknown severe IUGR may leads us to find a clue to resolve the mechanism of unknown severe IUGR Less
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