Objective: To analyze the characteristics of complex chromosomal rearrangement (CCR) in Chinese male carriers and its influence on male fertility.
Methods: Using the G band technique, we conducted karyotype analysis on the peripheral blood lymphocytes of 1,625 Chinese males with reproductive problems. We also searched CNKI and Wanfang database for CCR-related literature published between January 1984 and November 2013, followed by statistical analysis on the CCR characteristics and reproduction-related data of the CCR carriers.
Results: Two CCR carriers were found among the 1,625 males and another 47 cases identified from the databases. Among the 49 CCR carriers, there were 17 three-way exchange cases (34.7%), 17 double two-way exchange cases (34.7%), and 15 exceptional cases (30.6%), with no statistically significant differences in the incidence of the three types (P > 0.05). Azoospermia- or oligospermia-induced infertility was found in 19 (38.8% ) of the CCR carriers. A total of 87 pregnancies were achieved in the other 30 (61.2%), among which spontaneous abortion occurred in 75.9% (66/87), dead fetus and malformed infant death in 9.2% (8/87), and phenotypically normal offspring in 14.9% (13/87). Recurrent abortion was associated frequently with breakpoints on CCR-involved chromosomes 6, 7, 8, 11, and 16, while dyszoospermia mostly with breakpoints on CCR-involved chromosomes 10 and 14. The breaking occurred more than 3 times at 1p22, 1q25, 2q31, 5p13, 5q35, 6q23, 8q13, and 20p13. Moreo- ver, the breakpoints at 2q31, 5q35, and 8q13 were particularly related to recurrent abortion, while that at 1p22 only to dyszoospermia.
Conclusion: CCR is extremely rare. Male CCR carriers are often identified through reproductive problems and have high risks of infertility and abnormal pregnancy and a very low rate of normal newborns. In addition, chromosomes and breakpoints involved in CCR may affect the fertility of male CCR carriers, and some particular chromosomal breakpoints may play a key role in gametogenesis.