Prenatally diagnosed balanced chromosome rearrangements: eight years' experience.
OBJECTIVE
To investigate the incidence and pregnancy outcome of prenatally diagnosed balanced chromosome rearrangements from amniocentesis.


METHODS
Between January 1996 and December 2003, we collected cases with balanced chromosome rearrangements from amniocentesis specimens submitted to our cytogenetics laboratory for fetal karyotyping. Data on maternal age, indication for amniocentesis, detailed anatomic sonographic findings, gestational age at delivery, newborn birth weight and infant anomalies, if any, were obtained by chart review.


RESULTS
A total of 66 cases of balanced chromosomal translocations or inversions were identified from the 12,468 amniocentesis specimens. Specifically, 0.256% had a reciprocal translocation, 0.080% had a Robertsonian translocation, and 0.192% had an inversion. The incidences of de novo reciprocal translocations, Robertsonian translocations and inversions were 0.080%, 0.016% and 0.024%, respectively. Abnormal prenatal sonographic findings occurred in 2 cases, 1 in an inherited case and 1 in a de novo case. Abnormal postnatal findings occurred in 5 cases, 3 in inherited cases and 2 in de novo cases. Excluding the cases with minor congenital anomalies, the major congenital anomaly rates of inherited and de novo chromosome rearrangements were 1.96% and 6.66%, respectively.


CONCLUSIONS
The incidences of prenatally diagnosed de novo reciprocal translocations, de novo Robertsonian translocations and de novo inversions were higher than those reported in previous, larger series. The major congenital anomaly rates for inherited and de novo chromosome rearrangements were higher than the 1.4% congenital anomaly rate in our general population. Consequently, detailed ultrasound examination and parental karyotyping should be viewed as essential measures in dealing with prenatally diagnosed balanced chromosome rearrangements.
Peng
Hsiu-Huei
HH
Department of Obstetrics and Gynecology and Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Lin-ko Medical Center, Chang Gung University College of Medicine, Tao-Yuan, Taiwan, ROC.
Chao
An-Shine
AS
Wang
Tzu-Hao
TH
Chang
Yao-Lung
YL
Chang
Shuenn-Dyh
SD
D000328:Adult; D000649:Amniocentesis; D002869:Chromosome Aberrations / Q000706:statistics & numerical data; D025063:Chromosome Disorders / Q000175:diagnosis / Q000453:epidemiology*; D007446:Chromosome Inversion / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology* / Q000235:genetics; D014178:Translocation, Genetic