Abstract：
OBJECTIVE: We present low-level mosaic trisomy 17 at amniocentesis in a pregnancy associated with a favorable fetal outcome and cytogenetic discrepancy between cultured and uncultured amniocytes.
METHODS: A 32-year-old, primigravid woman underwent amniocentesis at 18 weeks of gestation because of an increased nuchal translucency thickness of 3 mm in the first trimester sonographic screening. Amniocentesis revealed a karyotype of 47,XX,+17 [2]/46,XX [20]. Among 22 colonies of cultured amniocytes, two colonies had a karyotype of 47,XX,+17, whereas the rest 20 colonies had a karyotype of 46,XX. Simultaneous array comparative genomic hybridization (aCGH) on the DNA extracted from uncultured amniocytes revealed arr (1-22,X) × 2 with no genomic imbalance. Prenatal ultrasound and parental karyotypes were normal. Quantitative fluorescence polymerase chain reaction (QF-PCR) analysis on the DNA extracted from the parental bloods and cultured amniocytes excluded uniparental disomy (UPD) 17. The woman was encouraged to continue the pregnancy. A normal 3178-g female baby was delivered at 38 weeks of gestation without any phenotypic abnormalities. The karyotypes of cord blood, umbilical cord and placenta were all 46, XX (40/40 cells). When follow-up at age six months, the neonate was normal in physical and psychosomatic development.
CONCLUSIONS: Low-level mosaic trisomy 17 at amniocentesis can be a transient and benign condition, and can be associated with a favorable fetal outcome and cytogenetic discrepancy between cultured and uncultured amniocytes.
METHODS: A 32-year-old, primigravid woman underwent amniocentesis at 18 weeks of gestation because of an increased nuchal translucency thickness of 3 mm in the first trimester sonographic screening. Amniocentesis revealed a karyotype of 47,XX,+17 [2]/46,XX [20]. Among 22 colonies of cultured amniocytes, two colonies had a karyotype of 47,XX,+17, whereas the rest 20 colonies had a karyotype of 46,XX. Simultaneous array comparative genomic hybridization (aCGH) on the DNA extracted from uncultured amniocytes revealed arr (1-22,X) × 2 with no genomic imbalance. Prenatal ultrasound and parental karyotypes were normal. Quantitative fluorescence polymerase chain reaction (QF-PCR) analysis on the DNA extracted from the parental bloods and cultured amniocytes excluded uniparental disomy (UPD) 17. The woman was encouraged to continue the pregnancy. A normal 3178-g female baby was delivered at 38 weeks of gestation without any phenotypic abnormalities. The karyotypes of cord blood, umbilical cord and placenta were all 46, XX (40/40 cells). When follow-up at age six months, the neonate was normal in physical and psychosomatic development.
CONCLUSIONS: Low-level mosaic trisomy 17 at amniocentesis can be a transient and benign condition, and can be associated with a favorable fetal outcome and cytogenetic discrepancy between cultured and uncultured amniocytes.
摘要：
目的：我们在妊娠羊膜腔穿刺术中呈现低水平镶嵌三体17，与良好的胎儿结局以及培养和未培养羊膜细胞之间的细胞遗传学差异相关。
方法：32岁，初产妇在妊娠18周时接受了羊膜穿刺术，因为在妊娠早期超声检查中颈部半透明厚度增加了3毫米。羊膜穿刺术显示核型为47，XX，+17[2]/46,XX[20]。在22个培养的羊膜细胞集落中，两个菌落的核型为47，XX，+17，而其余20个菌落的核型为46，XX。从未培养的羊膜细胞中提取的DNA上的同时阵列比较基因组杂交（aCGH）显示arr（1-22，X）×2，没有基因组失衡。产前超声和亲本核型正常。对从亲本血液和培养的羊膜细胞中提取的DNA进行定量荧光聚合酶链反应（QF-PCR）分析，排除了单亲二体（UPD）17。该妇女被鼓励继续怀孕。在妊娠38周时分娩了一个正常的3178-g女婴，没有任何表型异常。脐带血的核型,脐带和胎盘均为46,XX(40/40细胞)。在六个月的年龄进行随访时，新生儿身体和心身发育正常。
结论：羊膜穿刺术中低水平镶嵌三体17可能是一种短暂的良性疾病，并且可能与良好的胎儿结局以及培养的和未培养的羊膜细胞之间的细胞遗传学差异有关。
方法：32岁，初产妇在妊娠18周时接受了羊膜穿刺术，因为在妊娠早期超声检查中颈部半透明厚度增加了3毫米。羊膜穿刺术显示核型为47，XX，+17[2]/46,XX[20]。在22个培养的羊膜细胞集落中，两个菌落的核型为47，XX，+17，而其余20个菌落的核型为46，XX。从未培养的羊膜细胞中提取的DNA上的同时阵列比较基因组杂交（aCGH）显示arr（1-22，X）×2，没有基因组失衡。产前超声和亲本核型正常。对从亲本血液和培养的羊膜细胞中提取的DNA进行定量荧光聚合酶链反应（QF-PCR）分析，排除了单亲二体（UPD）17。该妇女被鼓励继续怀孕。在妊娠38周时分娩了一个正常的3178-g女婴，没有任何表型异常。脐带血的核型,脐带和胎盘均为46,XX(40/40细胞)。在六个月的年龄进行随访时，新生儿身体和心身发育正常。
结论：羊膜穿刺术中低水平镶嵌三体17可能是一种短暂的良性疾病，并且可能与良好的胎儿结局以及培养的和未培养的羊膜细胞之间的细胞遗传学差异有关。
