[Analysis of cytogenetic characteristics and fertility of carriers of complex chromosomal rearrangements from Henan region].

OBJECTIVE: To explore cytogenetic characteristics and fertility of carriers of complex chromosome rearrangements (CCR) from Henan region.

METHODS: G-banded karyotyping analysis was carried out on peripheral blood lymphocytes derived from 160 601 patients with reproductive abnormalities. Relevant literature was retrieved from domestic and overseas databases. Cytogenetic characteristics and clinical data of CCR carriers were analyzed.

RESULTS: Twenty-seven CCR carriers were identified among the 160 601 patients. In addition, 6 cases were identified from the database research. Among the 33 CCR carriers, there were 17 three- and four-way exchange cases (51.5%), 10 double two-way exchange cases (30.3%), and 6 unusual CCRs (18.2%). Infertility was noted in 14 (42.4%) of the CCR carries. A total of 38 pregnancies were achieved in the remaining 19 cases (57.6%), among which spontaneous abortions or embryonic losses have occurred in 89.5% (34/38), multiple congenital abnormalities have occurred in 7.9% (3/38), while phenotypically normal offspring have occurred in 2.6% (1/38). Chromosomes 1, 11, 2, 4, 5 and 12 were more frequently involved, with their breakpoints occurred more than 3 times at 1p22, 11q23, 12p13 and 22q11.

CONCLUSION: CCR carriers are at a higher risk for abnormal pregnancies. Even for those with normal pregnancy, prenatal diagnosis should be provided. Chromosomes and their breakpoints involved in CCR may affect the fertility of CCR carriers. Analyzing the types of CCR and involved chromosomes and breakpoints can facilitate genetic counseling for CCR carriers.