[Characteristics of complex chromosomal rearrangement in Chinese male carriers and its impact on male fertility].

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.