Prenatal diagnosis of de novo t(2;18;14)(q33.1;q12.2;q31.2), dup(5)(q34q34), del(7)(p21.1p21.1), and del(10)(q25.3q25.3) and a review of the prenatally ascertained de novo apparently balanced complex and multiple chromosomal rearrangements.
OBJECTIVE
To present the prenatal diagnosis of a de novo complex chromosomal rearrangement (CCR) associated with de novo interstitial deletions and duplication and to review the literature.


METHODS
Amniocentesis was performed at 18 weeks' gestation because of an increased risk for Down syndrome based on maternal serum alpha-fetoprotein and human chorionic gonadotrophin screening. Amniocentesis revealed a karyotype of 46,XY,t(2;18;14)(q33.1;q12.2;q31.2),dup(5)(q34q34),del(7)(p21.1p21.1), del(10)(q25.3q25.3). The parental karyotypes were normal. The pregnancy was terminated. The fetus manifested facial dysmorphism, clinodactyly of both hands, and hypoplasia of the left great toe. Spectral karyotyping (SKY), cytogenetic polymorphism, and polymorphic DNA markers were used to investigate the imbalances and the origin of the de novo aberrant chromosomes.


RESULTS
SKY showed a three-way CCR. Cytogenetic polymorphism investigation of the derivative chromosome 14 of the fetus and the parental chromosomes 14 determined the maternal origin of the translocation. Polymorphic DNA marker analysis confirmed the maternal origin of the de novo interstitial deletions and duplication. No cryptic imbalance at or near the breakpoints of the CCR was detected by the molecular analysis.


CONCLUSIONS
De novo apparently balanced CCRs may be associated with imbalances in other chromosomes. We suggest further investigation and re-evaluation of cryptic or subtle imbalances in all cases classified as de novo apparently balanced CCRs.
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China. cpc_mmh@yahoo.com
Chih-Ping
CP
Chen
Schu-Rern
SR
Chern
Chen-Chi
CC
Lee
Chyi-Chyang
CC
Lin
Yueh-Chun
YC
Li
Lie-Jiau
LJ
Hsieh
Wen-Lin
WL
Chen
Wayseen
W
Wang
D000015:Abnormalities, Multiple / Q000175:diagnosis* / Q000235:genetics; D000328:Adult; D000649:Amniocentesis; D002869:Chromosome Aberrations / Q000196:embryology*; D002872:Chromosome Deletion; D002883:Chromosomes, Human, Pair 14; D002887:Chromosomes, Human, Pair 18; D002889:Chromosomes, Human, Pair 2; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D020440:Gene Duplication; D006801:Humans; D007621:Karyotyping; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014178:Translocation, Genetic / Q000235:genetics