Abstract：
BACKGROUND: Trisomy 18 syndrome, also called Edwards syndrome, is the second most common autosomal trisomy after trisomy 21 that is caused by the presence of an extra copy of chromosome 18. Approximately 50% of infants with trisomy 18 cannot survive for more than 1 week and about 5 - 10% of children die within 1 year after birth. The aim of this study is to describe a 4-year-old female patient of mosaic trisomy 18 with normal prenatal ultrasound findings and maternal serum markers and to investigate the relationship between the percentage of trisomic cells and the major clinical phenotypes combined with other nine patients through a review of the literature.
METHODS: The patient\'s peripheral blood was examined by cytogenetic G-banding technique.
RESULTS: The cytogenetics results reported following the ISCN 2020 guideline as mos 47,XX,+18[87]/46,XX[13].
CONCLUSIONS: There is little correlation between various phenotypes of mosaic trisomy 18 and the percentage of trisomy cells in the patient\'s peripheral leukocytes. Although most of fetuses with mosaic trisomy 18 have abnormal ultrasound findings, it is necessary to highlight the possibility of normal findings during the pregnancy.
METHODS: The patient\'s peripheral blood was examined by cytogenetic G-banding technique.
RESULTS: The cytogenetics results reported following the ISCN 2020 guideline as mos 47,XX,+18[87]/46,XX[13].
CONCLUSIONS: There is little correlation between various phenotypes of mosaic trisomy 18 and the percentage of trisomy cells in the patient\'s peripheral leukocytes. Although most of fetuses with mosaic trisomy 18 have abnormal ultrasound findings, it is necessary to highlight the possibility of normal findings during the pregnancy.
摘要：
背景：18三体综合征，也叫爱德华兹综合症,是仅次于21三体的第二最常见的常染色体三体性，是由18号染色体的额外拷贝引起的。大约50%的18三体婴儿不能存活超过1周,并且大约5-10%的儿童在出生后1年内死亡。这项研究的目的是描述一名4岁的镶嵌三体性18女性患者，其产前超声检查结果和母体血清标志物正常，并研究三体细胞百分比与其他9例患者的主要临床表型之间的关系。通过文献回顾。
方法：采用细胞遗传学G显带技术检测患者外周血。
结果：根据ISCN2020指南，细胞遗传学结果报告为mos47，XX，+18[87]/46,XX[13]。
结论：患者外周血白细胞中镶嵌18三体的各种表型与三体细胞的百分比之间几乎没有相关性。尽管大多数患有马赛克18三体的胎儿都有异常的超声检查结果，有必要强调怀孕期间正常发现的可能性。
方法：采用细胞遗传学G显带技术检测患者外周血。
结果：根据ISCN2020指南，细胞遗传学结果报告为mos47，XX，+18[87]/46,XX[13]。
结论：患者外周血白细胞中镶嵌18三体的各种表型与三体细胞的百分比之间几乎没有相关性。尽管大多数患有马赛克18三体的胎儿都有异常的超声检查结果，有必要强调怀孕期间正常发现的可能性。
