RESEARCH LETTER
Rapid diagnosis of monosomy X using uncultured amniocytes in amniotic fluid
and cultured lymphocytes in cystic fluid in a pregnancy with fetal cystic
hygroma and hydrops
Chih-Ping Chen1,2,3,4,5,6,7*, Chin-Yuan Hsu2, Schu-Rern Chern3, Peih-Shan Wu8, Jun-Wei Su2,9, Chen-Chi Lee2 and Wayseen Wang3,10
1Department of Medicine, Mackay Medical College, New Taipei City, Taiwan
2Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan 3Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
4Department of Biotechnology, Asia University, Taichung, Taiwan
5School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan 6Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan 7Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei,
Taiwan
8Gene Biodesign Co. Ltd, Taipei, Taiwan
9Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan 10Department of Bioengineering, Tatung University, Taipei, Taiwan
* Correspondence to: Chih-Ping Chen, MD
Department of Obstetrics and Gynecology, Mackay Memorial Hospital 92, Section 2, Chung-Shan North Road, Taipei, Taiwan
Tel: +886-2-25433535; Fax: +886-2-25433642, +886-2-25232448 E-mail: [email protected]
Short title: Rapid diagnosis of monosomy X
A 40-year-old, primigravid woman was referred for amniocentesis at 17 weeks of gestation because of nuchal edema. Prenatal ultrasound at 17 weeks of gestation showed cystic hygroma, pleural effusion and hydrops fetalis (Fig. 1). About 26 mL amniotic fluid was aspired, of which 10 mL was applied for array comparative genomic hybridization (aCGH) using uncultured amniocytes, and 16 mL was applied for conventional cytogenetic analysis using cultured amniocytes. About 10 mL cystic fluid of cystic hygroma was aspired, and conventional cytogenetic analysis was made using cultured lymphocytes in the cystic fluid. The aCGH investigation using whole-genome ISCA Plus Cytogenetic array (Roche NimbleGen, Madison, WI, USA) on uncultured amniocytes revealed monosomy X and absence of Y chromosome (Fig. 2). Conventional cytogenetic analysis using cultured lymphocytes in the cystic fluid of cystic hygroma revealed a karyotype of 45,X (Fig. 3). The cultured amniocytes also showed a karyotype of 45,X. Quantitative fluorescent polymerase chain reaction (QF-PCR) assays revealed presence of the X chromosome of maternal origin and absence of the X chromosome of paternal origin (Fig. 4). The pregnancy was terminated at 19 weeks of gestation, and a 370-g hydropic fetus was delivered with cystic hygroma and hydrops fetalis (Fig. 5).
Rapid aneuploidy diagnosis (RAD) refers to the application of molecular cytogenetic technologies such as interphase fluorescence in situ hybridization (FISH), QF-PCR, multiplex ligation-dependent probe amplification (MLPA) and aCGH for rapid prenatal diagnosis of aneuploidy without the need of cell culture [1-3]. In the present case, aCGH using uncultured amniocytes is useful for RAD in a pregnancy with fetal major malformations. The present case also shows that the lymphocytes in the cystic fluid of cystic hygroma are as useful as cord blood lymphocytes for rapid cytogenetic analysis.
About 75% of second-trimester fetuses with cystic hygroma have chromosomal abnormalities of which 80% are 45,X [4]. Azar et al [4] found that among 44 second-trimester fetuses with cystic hygroma, 33 cases had aneuploidy including Turner syndrome (n = 31), trisomy 18 (n = 1) and trisomy 21 (n = 1). Snijders et al [5] found that among 276 fetuses with cystic hygroma, about 77% of the cases had aneuploidy, including 45,X (n = 163), trisomy 21 (n = 26), trisomy 18 (n = 13) and other rearrangements (n = 11). Snijders et al [5] also found that cystic hygroma appeared in 88% of fetal Turner syndrome (n = 65), 2% of fetal trisomy 18 (n = 137) and 1% of fetal trisomy 21 (n = 38).
In conclusion, prenatal diagnosis of cystic hygroma should raise a suspicion of aneuploidy. We suggest that aCGH using uncultured amniocytes is useful for RAD, and aspiration of cystic fluid is as useful as cordocentesis for rapid cytogenetic analysis.
Acknowledgements
This work was supported by research grant NSC-99-2628-B-195-001-MY3 from the National Science Council, and MMH-E-100-04 from Mackay Memorial Hospital, Taipei, Taiwan.
References
1. Chen C-P, Su Y-N, Tsai F-J, Chern S-R, Hsu C-Y, Huang M-C, et al. Rapid genome-wide aneuploidy diagnosis using uncultured amniocytes and array comparative genomic hybridization in pregnancy with abnormal ultrasound findings detected in late second and third trimesters. Taiwan J Obstet Gynecol 2010; 49: 120-3.
2. Chen C-P, Su Y-N, Lin S-Y, Chang C-L, Wang Y-L, Huang J-P, et al. Rapid aneuploidy diagnosis by multiplex ligation-dependent probe amplification and array comparative genomic hybridization in pregnancy with major congenital malformations. Taiwan J Obstet Gynecol 2011a; 50: 85-94
3. Chen C-P, Su Y-N, Wu P-C, Lee C-C, Pan C-W, Wang W. Rapid aneuploidy diagnosis by array comparative genomic hybridization using uncultured amniocytes in a pregnancy with fetal nuchal edema and mild ascites. J Med Ultrasound 2011b; 19: 64-7.
4. Azar GB, Snijders RJ, Gosden C, Nicolaides KH. Fetal nuchal cystic hygromata: associated malformations and chromosomal defects. Fetal Diagn Ther 1991; 6: 46-57.
5. Snijders RJM, Farrias M, von Kaisenberg C, Nicolaides KH. Fetal abnormalities. In: Snijders RJM, Nicolaides KH, eds. Ultrasound Markers for Fetal Chromosomal Defects. New York: Parthenon Publishing Group, 1996; 1-62.
Figure Legends
Fig. 1. Prenatal ultrasound at 17 weeks of gestation shows (A) cystic hygroma, (B) pleural effusion and (C) hydrops fetalis.
Fig. 2. Array comparative genomic hybridization analysis on uncultured amniocytes shows monosomy X and absence of Y chromosome.
Fig. 3. Cytogenetic analysis of cultured lymphocytes in the cystic fluid of cystic hygroma shows a karyotype of 45,X.
Fig. 4. Representative electrophoretograms of polymorphic DNA markers specific for chromosome X show that the fetus inherits only the maternal allele, indicating a paternal origin of absence of one X chromosome in the fetus.
Fig 5. The fetus at birth.
