Abstract：
OBJECTIVE: We present low-level mosaic trisomy 13 at amniocentesis in a pregnancy associated with a positive non-invasive prenatal testing (NIPT) result suspicious of trisomy 13, a chorionic villus sampling (CVS) result of mosaic trisomy 13, cytogenetic discrepancy in various tissues and a favorable fetal outcome.
METHODS: A 29-year-old, gravida 2, para 1, woman underwent amniocentesis at 20 weeks of gestation because of a positive NIPT result (Z-score = 20.9, positive ≥3) suspicious of trisomy 13 at 11 weeks of gestation and a CVS result of mosaic trisomy 13 at 14 weeks of gestation. At 14 weeks of gestation, CVS revealed the multiplex ligation-dependent probe amplification (MLPA) result of rea X,Y (P095) × 1, 13 (P095) × 3, 18,21 (P095) × 2/X,Y (P095) × 1, 13,18,21 (P095) × 2 and a karyotype of 48,XY,+13,+mar [9]/47,XY,+mar[16]. She was referred to the hospital for genetic counseling at 15 weeks of gestation, and cytogenetic analysis of parental blood revealed 47,XY,+mar in the father and 46, XX in the mother. Fluorescence in situ hybridization (FISH) analysis on the paternal blood showed that the extra dicentric marker was derived from chromosome 15 without the locus SNRPN (15q11.2), and the result was 47,XY,+mar.ish dic(15) (D15Z1++, SNRPN-, PML-)[20]. Amniocentesis at 20 weeks of gestation revealed a karyotype of 47,XY,+mar pat (20/20). Simultaneous interphase FISH analysis on uncultured amniocytes revealed 32% (32/100 cells) mosaicism for trisomy 13. Quantitative fluorescence polymerase chain reaction (QF-PCR) analysis using the DNA extracted from the parental bloods and uncultured amniocytes excluded uniparental disomy (UPD) 13. Prenatal ultrasound findings were normal. The woman was advised to continue the pregnancy, and a phenotypically normal 2708-g male baby was delivered at 38 weeks of gestation, The cord blood, umbilical cord and placenta had the karyotypes of 47,XY,+mar pat and did not have UPD 13. When follow-up at age two months, the neonate was phenotypically normal. FISH analysis on buccal mucosal cells detected 5.3% (5/95 cells) mosaicism for trisomy 13, compared with 0% in the normal control.
CONCLUSIONS: Low-level mosaic trisomy 13 at amniocentesis can be associated with a positive NIPT result suspicious of trisomy 13, a CVS result of mosaic trisomy 13, cytogenetic discrepancy in various tissues and a favorable fetal outcome.
METHODS: A 29-year-old, gravida 2, para 1, woman underwent amniocentesis at 20 weeks of gestation because of a positive NIPT result (Z-score = 20.9, positive ≥3) suspicious of trisomy 13 at 11 weeks of gestation and a CVS result of mosaic trisomy 13 at 14 weeks of gestation. At 14 weeks of gestation, CVS revealed the multiplex ligation-dependent probe amplification (MLPA) result of rea X,Y (P095) × 1, 13 (P095) × 3, 18,21 (P095) × 2/X,Y (P095) × 1, 13,18,21 (P095) × 2 and a karyotype of 48,XY,+13,+mar [9]/47,XY,+mar[16]. She was referred to the hospital for genetic counseling at 15 weeks of gestation, and cytogenetic analysis of parental blood revealed 47,XY,+mar in the father and 46, XX in the mother. Fluorescence in situ hybridization (FISH) analysis on the paternal blood showed that the extra dicentric marker was derived from chromosome 15 without the locus SNRPN (15q11.2), and the result was 47,XY,+mar.ish dic(15) (D15Z1++, SNRPN-, PML-)[20]. Amniocentesis at 20 weeks of gestation revealed a karyotype of 47,XY,+mar pat (20/20). Simultaneous interphase FISH analysis on uncultured amniocytes revealed 32% (32/100 cells) mosaicism for trisomy 13. Quantitative fluorescence polymerase chain reaction (QF-PCR) analysis using the DNA extracted from the parental bloods and uncultured amniocytes excluded uniparental disomy (UPD) 13. Prenatal ultrasound findings were normal. The woman was advised to continue the pregnancy, and a phenotypically normal 2708-g male baby was delivered at 38 weeks of gestation, The cord blood, umbilical cord and placenta had the karyotypes of 47,XY,+mar pat and did not have UPD 13. When follow-up at age two months, the neonate was phenotypically normal. FISH analysis on buccal mucosal cells detected 5.3% (5/95 cells) mosaicism for trisomy 13, compared with 0% in the normal control.
CONCLUSIONS: Low-level mosaic trisomy 13 at amniocentesis can be associated with a positive NIPT result suspicious of trisomy 13, a CVS result of mosaic trisomy 13, cytogenetic discrepancy in various tissues and a favorable fetal outcome.
摘要：
目的：我们介绍了在羊膜穿刺术中的低水平镶嵌三体13与阳性的非侵入性产前检测（NIPT）结果有关的妊娠，怀疑三体13，镶嵌三体13的绒毛膜绒毛取样（CVS）结果，各种组织中的细胞遗传学差异和良好的胎儿结局。
方法：29岁，妊娠2，第1段，女性在妊娠20周时接受了羊膜穿刺术，因为在妊娠11周时NIPT结果阳性（Z评分=20.9，阳性≥3），怀疑三体13在妊娠14周时的CVS结果。妊娠14周时，CVS揭示了reaX的多重连接依赖性探针扩增(MLPA)结果，Y(P095)×1,13(P095)×3,18,21(P095)×2/X,Y(P095)×1,13,18,21(P095)×2,核型为48,XY,+13,+mar[9]/47,XY,+mar[16]。她在怀孕15周时被转诊到医院接受遗传咨询，父母血液的细胞遗传学分析显示47，XY，父亲在+3，母亲在46，XX。父系血液的荧光原位杂交（FISH）分析表明，额外的双中心标记来自没有SNRPN位点的15号染色体（15q11.2），结果是47，XY，+mar。ishdic(15)(D15Z1++,SNRPN-,PMI-)[20]。妊娠20周时的羊膜穿刺术显示核型为47，XY，+马尔帕特（20/20）。对未培养的羊膜细胞进行的同时间期FISH分析显示，三体性13具有32％（32/100细胞）的镶嵌性。使用从亲本血液和未培养的羊膜细胞中提取的DNA进行的定量荧光聚合酶链反应（QF-PCR）分析排除了单亲二体（UPD）13。产前超声检查结果正常。建议该妇女继续怀孕，一名表型正常的2708克男婴在妊娠38周时分娩，脐带血,脐带和胎盘的核型为47，XY，+marpat，没有UPD13。当在两个月的年龄进行随访时，新生儿表型正常.对13三体的颊粘膜细胞的FISH分析检测到5.3％（5/95细胞）镶嵌性，而正常对照为0％。
结论：羊膜穿刺术中低水平镶嵌三体性13可能与怀疑三体性13的阳性NIPT结果，镶嵌三体性13的CVS结果，各种组织的细胞遗传学差异和良好的胎儿结局有关。
方法：29岁，妊娠2，第1段，女性在妊娠20周时接受了羊膜穿刺术，因为在妊娠11周时NIPT结果阳性（Z评分=20.9，阳性≥3），怀疑三体13在妊娠14周时的CVS结果。妊娠14周时，CVS揭示了reaX的多重连接依赖性探针扩增(MLPA)结果，Y(P095)×1,13(P095)×3,18,21(P095)×2/X,Y(P095)×1,13,18,21(P095)×2,核型为48,XY,+13,+mar[9]/47,XY,+mar[16]。她在怀孕15周时被转诊到医院接受遗传咨询，父母血液的细胞遗传学分析显示47，XY，父亲在+3，母亲在46，XX。父系血液的荧光原位杂交（FISH）分析表明，额外的双中心标记来自没有SNRPN位点的15号染色体（15q11.2），结果是47，XY，+mar。ishdic(15)(D15Z1++,SNRPN-,PMI-)[20]。妊娠20周时的羊膜穿刺术显示核型为47，XY，+马尔帕特（20/20）。对未培养的羊膜细胞进行的同时间期FISH分析显示，三体性13具有32％（32/100细胞）的镶嵌性。使用从亲本血液和未培养的羊膜细胞中提取的DNA进行的定量荧光聚合酶链反应（QF-PCR）分析排除了单亲二体（UPD）13。产前超声检查结果正常。建议该妇女继续怀孕，一名表型正常的2708克男婴在妊娠38周时分娩，脐带血,脐带和胎盘的核型为47，XY，+marpat，没有UPD13。当在两个月的年龄进行随访时，新生儿表型正常.对13三体的颊粘膜细胞的FISH分析检测到5.3％（5/95细胞）镶嵌性，而正常对照为0％。
结论：羊膜穿刺术中低水平镶嵌三体性13可能与怀疑三体性13的阳性NIPT结果，镶嵌三体性13的CVS结果，各种组织的细胞遗传学差异和良好的胎儿结局有关。
