MCDA twins with discordant malformations: submicroscopic chromosomal anomalies detected by chromosomal microarray analysis and clinical outcomes.
OBJECTIVE
To evaluate whether discrepant copy number variations (CNVs) contribute to the risk for discordant congenital anomalies in monochorionic diamniotic (MCDA) twins.


METHODS
We conducted a parallel testing using both G-banding for standard karyotyping and chromosomal microarray analysis (CMA) with Affymetrix CytoScan HD array in MCDA twins with discordant malformations.


RESULTS
During the study period, 193 MCDA twins with discordant malformations were detected and followed up. Multiple anomalies and cardiac defects were detected most frequently among the fetuses with malformations. Among all the 119 MCDA twins that were successfully performed fetal karyotyping, discordance of chromosomal aberrations were identified in nine cases, including one with discordant trisomy 18, seven with discordant monosomy X, one twin with 47, XXY and the co-twin with 45, X [7]/46, XY[43]. CMA revealed pathological CNVs in four out of the 110 fetuses with normal karyotype and the detection rate of uncertain clinical significance was 3.6% (4/110). Discordance of CNVs was detected in 5.5% (3/55) among the 55 MCDA twins with normal karyotype. Monozygosity was confirmed in all the 61 MCDA twins that were performed CMA.


CONCLUSIONS
Large whole chromosome abnormalities are more common between discordant twins rather than smaller CNVs in this study. © 2016 John Wiley & Sons, Ltd.
Department of Ultrasonic Medicine, Fetal Medical Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Ruan
R
Peng
Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Yi
Y
Zhou
Department of Ultrasonic Medicine, Fetal Medical Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Hong-Ning
HN
Xie
Department of Ultrasonic Medicine, Fetal Medical Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Ju
J
Zheng
Department of Ultrasonic Medicine, Fetal Medical Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Ying-Jun
YJ
Xie
Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Jian-Bo
JB
Yang
D000293:Adolescent; D000328:Adult; D025063:Chromosome Disorders / Q000175:diagnosis / Q000235:genetics*; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D000013:Congenital Abnormalities / Q000000981:diagnostic imaging / Q000235:genetics*; D056915:DNA Copy Number Variations / Q000235:genetics*; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006801:Humans; D007621:Karyotyping; D007713:Klinefelter Syndrome / Q000175:diagnosis / Q000235:genetics; D046228:Microarray Analysis; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011296:Prenatal Diagnosis; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics; D000073842:Trisomy 18 Syndrome; D014424:Turner Syndrome / Q000175:diagnosis / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics*; D055815:Young Adult