Objective: The aim of this study was to compare the frequency of chromosomal translocations in postnatal and prenatal cases in a single laboratory in China, and to investigate the rates and indications of chromosomal translocations in postnatal diagnosis and prenatal diagnosis. Study design: 17,991 postnatal cases with reproductive failure or congenital anomalies and 4198 prenatal cases with indications for amniocentesis in Northeast China were enrolled. Chromosomal karyotype analysis was performed on blood samples and amniotic fluid samples with standard G-banding. In prenatal cases found to have chromosomal translocations, the couples were recalled for performing karyotype analysis to analyze the origin of chromosomal translocations. Results: The frequency of chromosomal translocations in postnatal cases (1.26%, 227/17991) was statistically significant difference as compared with prenatal cases (0.64%, 27/4198). According to the reasons for postnatal diagnosis, the highest incidence of chromosomal translocations was found in cases with congenital anomalies (2.04%), followed by recurrent miscarriages (1.75%), infertility (1.06%) and previous abnormal offspring (0.74%). For prenatal diagnosis, the highest incidence of translocations was found in cases with the indication of parent with abnormal karyotype (27.72%), followed by previous abnormal child (3.12%), abnormal ultrasound findings (1.46%), advanced maternal age (0.47%), biochemical abnormal screening (0.42%). There were 12 cases of unbalanced translocations detected in postnatal cases and 4 cases in prenatal cases. Conclusion: The incidences of chromosomal translocation in patients with different indication make a big difference. The reason for ascertainment of the translocation should be taken into account when counseling these patients.
[1]Jilin Univ, Dept Reprod Med & Prenatal Diag, Hosp 1, 71 Xinmin St, Changchun 130021, Jilin, Peoples R China.
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