Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
Taiwan J Obstet Gynecol. 2020 Mar;59(2):327-330. doi: 10.1016/j.tjog.2020.01.026.
We present prenatal diagnosis of low-level mosaic trisomy 20 by amniocentesis in a pregnancy with a favorable outcome.
A 35-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XX,+20[8]/46,XX[23]. The parental karyotypes were normal, and prenatal ultrasound findings were unremarkable. Repeat amniocentesis performed at 20 weeks of gestation revealed a karyotype of 47,XX,+20[2]/46,XX[19]. Simultaneous molecular cytogenetic tests using uncultured amniocytes revealed no genomic imbalance in array comparative genomic hybridization (aCGH) analysis and a mosaic level of 14.3% (15/105 cells) in interphase fluorescence in situ hybridization (FISH) analysis. Polymorphic DNA marker analysis using the DNAs extracted from uncultured amniocytes and parental bloods excluded uniparental disomy 20. At 39 weeks of gestation, a phenotypically normal 3580-g female baby was delivered without any structural abnormality. The neonate was doing well at age two years during postnatal follow-ups. Her psychomotor development was normal. Interphase FISH analysis of urinary cells revealed no trisomy 20 signals in 45/45 urinary cells. The peripheral blood had a karyotype of 46,XX in 40/40 lymphocytes.
Fetuses with low-level mosaic trisomy 20 at amniocentesis can have a favorable outcome. Molecular cytogenetic analysis on uncultured amniocytes is useful for confirmatory diagnosis of the mosaic level in case of mosaic trisomy 20 at amniocentesis with different mosaic levels at different amniocenteses.
我们通过羊水穿刺术对一例低水平嵌合体 20 三体妊娠进行产前诊断，该妊娠结局良好。
一名 35 岁女性因高龄接受了 17 周妊娠的羊水穿刺术。羊水穿刺术显示核型为 47,XX,+20[8]/46,XX[23]。父母的核型正常，产前超声检查未见异常。20 周妊娠时再次行羊水穿刺术，显示核型为 47,XX,+20[2]/46,XX[19]。同时对未培养的羊水细胞进行非培养性分子细胞遗传学检测，在 array 比较基因组杂交（aCGH）分析中未发现基因组不平衡，在间期荧光原位杂交（FISH）分析中嵌合体水平为 14.3%（15/105 个细胞）。使用未培养的羊水细胞和父母血液提取的 DNA 进行多态性 DNA 标记分析，排除了 20 号染色体单亲二体性。39 周妊娠时，分娩出一名表型正常的 3580g 女婴，无任何结构异常。新生儿在产后随访期间两岁时状况良好。她的精神运动发育正常。尿液细胞的间期 FISH 分析显示 45/45 个尿液细胞中没有 20 三体信号。外周血在 40/40 个淋巴细胞中有 46,XX 核型。
羊水穿刺术发现低水平嵌合体 20 三体的胎儿可能有良好的结局。在羊水穿刺术发现嵌合体 20 三体且不同次羊水穿刺术存在不同嵌合体水平的情况下，对未培养的羊水细胞进行分子细胞遗传学分析有助于确认嵌合体水平。
