Prenatal diagnosis and molecular cytogenetic characterization of low-level true mosaicism for trisomy 21 using uncultured amniocytes

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• 作者：Chih-Ping Chen^a ; ^b ; ^c ; ^d ; ^e ; ^f ; ^{cpc_mmh@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Yeou-Lih Wang^a ; ^g ; Schu-Rern Chern^b ; Peih-Shan Wu^h ; Yen-Ni Chen^a ; Shin-Wen Chen^a ; Li-Feng Chen^a ; Meng-Shan Lee^a ; Chien-Wen Yang^b ; Wayseen Wang^b ; ⁱ
• 关键词：aCGH ; interphase FISH ; mosaicism ; trisomy 21 ; uncultured amniocytes
• 刊名：Taiwanese Journal of Obstetrics and Gynecology
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：55
• 期：2
• 页码：285-287
• 全文大小：687 K

文摘

We present a prenatal diagnosis and molecular cytogenetic characterization of low-level true mosaicism for trisomy 21 using uncultured amniocytes.

Case report

A 35-year-old woman presented with a borderline-positive result of noninvasive prenatal testing for trisomy 21. She underwent amniocentesis at 18 weeks of gestation, which revealed a karyotype of 47,XY,+21(5)/46,XY(53). Repeat amniocentesis at 22 weeks of gestation revealed a karyotype of 47,XY,+21(6)/46,XY(26). Array comparative genomic hybridization (aCGH) analysis on uncultured amniocytes revealed mosaic levels of 10% to 15% for trisomy 21. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed a mosaic level of 21.7% (28/129 cells) for trisomy 21. Following genetic counseling and detailed ultrasound examination, the parents decided to continue the pregnancy. The pregnancy was carried to term, and a normal 3664-g male baby was delivered. The cord blood lymphocytes had a karyotype of 47,XY,+21(2)/46,XY(38). Postnatal interphase FISH analysis of urine detected no trisomy 21 in all 39/39 urinary cells. The neonate was phenotypically normal at age 7 months.

Conclusion

Low-level true mosaicism for trisomy 21 can be associated with a favorable fetal outcome. aCGH and interphase FISH analyses on uncultured amniocytes are useful for rapid confirmation of low-level true mosaicism for trisomy 21 at repeated amniocentesis.