目的:我们在产前诊断中提出了与良好胎儿结局相关的妊娠中的马赛克远端9p缺失。
方法:34岁,由于母亲年龄高,初产妇在妊娠17周时接受了羊膜穿刺术。羊膜穿刺术显示核型为46,XY,del(9)(p23)[8]/46,XY[17]。对从未培养的羊膜细胞提取的DNA进行的同时阵列比较基因组杂交(aCGH)分析显示,9p24.3p23缺失的镶嵌性为43%。产前超声怀疑尿道下裂和回声肠。妊娠23周时,她被推荐接受遗传咨询,重复羊膜穿刺术显示核型为46,XY,del(9)(p23)[10]/46,XY[10]。亲本核型正常。未培养的羊膜细胞的分子遗传学分析显示,通过定量荧光聚合酶链反应(QF-PCR)和aCGH的arr9p24.3p23×1.55(40%-50%镶嵌性)没有单亲二体(UPD)9。妊娠27周时,她接受了第三次羊膜穿刺术,结果显示染色体核型为46,XY,del(9)(p23)[6]/46,XY[14]。从未培养的羊膜细胞中提取的DNA的同时aCGH分析显示了arr9p24.3p23(35%镶嵌性)的结果。产前超声检查正常。建议她继续怀孕,一个3020克表型正常的男婴在妊娠41周时分娩。出生时,脐带血的核型,脐带和胎盘分别为46,XY,del(9)(p23)[7]/46,XY[37],46,XY,del(9)(p23)[17]/46,XY[23]和46,XY在40/40细胞,分别。在三个月的年龄进行随访时,新生儿表型和发育正常。外周血核型为46,XY,del(9)(p23)[3]/46,XY[37],和口腔粘膜细胞的相间荧光原位杂交(FISH)分析显示,远端9p缺失具有13%(13/102个细胞)的镶嵌性。
结论:产前诊断时正常细胞系的Mosaic远端9p缺失可能与良好的胎儿结局和非整倍体细胞系的围产期进行性减少有关。
OBJECTIVE: We present mosaic distal 9p deletion at prenatal diagnosis in a pregnancy associated with a favorable fetal outcome.
METHODS: A 34-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY, del(9)(p23)[8]/46,XY[17]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes showed 43% mosaicism for the 9p24.3p23 deletion. Prenatal ultrasound suspected hypospadias and echogenic bowel. At 23 weeks of gestation, she was referred for genetic counseling, and repeat amniocentesis revealed a karyotype of 46,XY,del(9)(p23)[10]/46,XY[10]. The parental karyotypes were normal. Molecular genetic analysis on uncultured amniocytes revealed no uniparental disomy (UPD) 9 by quantitative fluorescence polymerase chain reaction (QF-PCR) and arr 9p24.3p23 × 1.55 (40%-50% mosaicism) by aCGH. At 27 weeks of gestation, she underwent the third amniocentesis which revealed a karyotype of 46,XY,del(9)(p23)[6]/46,XY[14]. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes revealed the result of arr 9p24.3p23 (35% mosaicism). Prenatal ultrasound was normal. She was advised to continue the pregnancy, and a 3020-g phenotypically normal male baby was delivered at 41 weeks of gestation. At birth, the karyotypes of cord blood, umbilical cord and placenta were 46,XY,del(9)(p23)[7]/46,XY[37], 46,XY,del(9)(p23)[17]/46,XY[23] and 46,XY in 40/40 cells, respectively. When follow-up at age three months, the neonate was normal in phenotype and development. The peripheral blood had a karyotype of 46,XY,del(9)(p23)[3]/46,XY[37], and interphase fluorescence in situ hybridization (FISH) analysis on buccal mucosal cells showed 13% (13/102 cells) mosaicism for the distal 9p deletion.
CONCLUSIONS: Mosaic distal 9p deletion with a normal cell line at prenatal diagnosis can be associated with a favorable fetal outcome and perinatal progressive decrease of the aneuploid cell line.