A rare complex chromosomal rearrangement in an oligospermic male: a case report and review of the Chinese literature

Analysis of complex chromosomal rearrangements using a combination of current molecular cytogenetic techniques

BACKGROUND

Using combined fluorescence in situ hybridization (FISH) and high-throughput whole-genome sequencing (WGS) molecular cytogenetic technology, we aim to analyze the junction breakpoints of complex chromosome rearrangements (CCR) that were difficult to identify by conventional karyotyping analysis and further characterize the genetic causes of recurrent spontaneous abortion.

RESULTS

By leveraging a combination of current molecular techniques, including chromosome karyotype analysis, FISH, and WGS, we comprehensively characterized the extremely complex chromosomal abnormalities in this patient with recurrent spontaneous abortions. Here, we demonstrated that combining these current established molecular techniques is an effective and efficient workflow to identify the structural abnormalities of complex chromosomes and locate the rearrangement of DNA fragments.

CONCLUSIONS

In conclusion, leveraging results from multiple molecular and cytogenetic techniques can provide the most comprehensive genetic analysis for genetic etiology research, diagnosis, and genetic counseling for patients with recurrent spontaneous abortion and embryonic abortion.

Complex Chromosomal Rearrangement: A Case Report to Emphasize the Need for Parental Karyotyping and Genetic Counseling

Complex chromosomal rearrangements (CCRs) are rare structural rearrangements which involve at least three or more chromosomal breaks. The present report emphasizes the significance of parental karyotyping and the need of genetic counseling for couples with bad obstetric history (repeated abortions/miscarriages). The report includes the cytogenetic assessment of the proband and the mother, carried out at our accredited laboratory. The karyotype analysis of the proband revealed an apparently balanced translocation, identified to have been familially inherited from the mother having CCRs with double two-way translocations involving four chromosomes.

Two cases of complex balanced autosomal translocations associated with severe oligozoospermia

Complex balanced autosomal translocation is rare and can lead to impaired spermatogenesis in males; however, its effects on oligozoospermia have rarely been reported. We report here two cases of rare complex balanced translocation in men with infertility. The karyotype of the first case was 46,XY,der(1)t(1;12)(p22;p11.2)ins(9;1)(p24;q25q23),der(9)ins(9;1),der(12)t(1;12)·ish der(1)t(1;12)(RP11-636B1+;RP11-659D23+)ins(9;1)(RP11-118P13+),der(9)ins(9;1),der(12)t(1;12). And the patient showed severe oligozoospermia with adult schizophrenia without other abnormalities. The karyotype of the second patient was 46,XY,der(5)t(5;11)(q14;p11.2),der(11)t(11;18)(p11.2;q11.2),der(18)t(5,18)(q14;p11.3)add(18)(q11.2?)·ish der(5)t(5;11)(RP11-846K3+,RP11-89B9+),der(11)t(11;18)(RP11-89B9-,RP11-170L12+,RP11-469N6+),der(18)t(5;18)(RP11-125L2+,RP11-29M13+)add(18)(q11.2?), and the patient displayed severe oligozoospermia without other abnormalities. The two cases were verified by fluorescent in situ hybridization, and no abnormalities were found by genome-wide copy number variation analysis. To our knowledge, these two cases of complex autosomal karyotypes have not been reported previously. Although rare, these cases suggest that complex balanced translocations may be important causes of oligozoospermia. We speculate that the balanced translocation hinders germ cell meiosis and causes impaired spermatogenesis. Accordingly, the two reported patients have very low probabilities of giving birth to a normal child; therefore, we suggest choosing donor semen or adopting a child.