• Journal of Genetic Medicine
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• 제3권1호
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• pp.25-27
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• 1999

Purpose: To present our experiences in pseudomosaicism or maternal cell contamination in genetic mid-trimester amniocentesis confirmed through percutaneous umbilical blood sampling. Methods: From 1992 to 1997, repeated cytogenetic evaluation with fetal cord blood was carried out in 14 cases showing mosaic patterns. Results: We confirmed pseudomosaicism in 12 cases (85.7%) by repeated cytogenetic evaluation, and also maternal cell contamination in 2 cases. Conclusion: Repeated cytogenetic evaluation via percutaneous umbilical blood sampling was a rapid and useful method for the confirmation of mosaicism resulted from genetic mid-trimester amniocentesis.

• Journal of Genetic Medicine
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• 제19권2호
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• pp.43-48
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• 2022

A prenatal chromosomal microarray (CMA) is generally recommended when a major anomaly is suspected on prenatal ultrasonography. As it can overcome the limitations of conventional karyotyping, it is expected that the number of prenatal CMA test requests will gradually increase. However, given the specificity of prenatal diagnosis, there are practical considerations compared to postnatal testing, such as the validation of prenatal specimens, maternal cell contamination, precautions when reporting variants of uncertain significance, and the need for comprehensive genetic counseling considering secondary findings. The purpose of this article is to provide necessary information to health care providers in consideration of these issues and to provide appropriate genetic counseling to patients.

• Journal of Genetic Medicine
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• 제11권2호
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• pp.43-48
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• 2014

Chorionic villus sampling has gained importance as a tool for early cytogenetic diagnosis with a shift toward first trimester screening. First trimester screening using nuchal translucency and biomarkers is effective for screening. Chorionic villus sampling generally is performed at 10-12 weeks by either the transcervical or transabdominal approach. There are two methods of analysis; the direct method and the culture method. While the direct method may prevent maternal cell contamination, the culture method may be more representative of the true fetal karyotype. There is a concern for mosaicism which occurs in approximately 1% of cases, and mosaic results require genetic counseling and follow-up amniocentesis or fetal blood sampling. In terms of complications, procedure-related pregnancy loss rates may be the same as those for amniocentesis when undertaken in experienced centers. When the procedure is performed after 9 weeks gestation, the risk of limb reduction is not greater than the risk in the general population. At present, chorionic villus sampling is the gold standard method for early fetal karyotyping; however, we anticipate that improvements in noninvasive prenatal testing methods, such as cell free fetal DNA testing, will reduce the need for invasive procedures in the near future.