Balanced complex chromosome rearrangement in male infertility: case report and literature review

Abstract

Complex chromosome rearrangements (CCRs) are structural rearrangements involving at least three chromosomes and three or more chromosome breakpoints. Generally, balanced CCR carriers have a normal phenotype but they are at a higher reproductive risk. Azoospermia was discovered in the male partner of a couple with primary infertility. Conventional cytogenetics identified a CCR refined by fluorescent in situ hybridisation. The CCR involved three chromosomes, four breakpoints and an insertion. A literature search identified 43 phenotypically normal males referred for reproductive problems presenting a CCR. More males were ascertained because of spermatogenesis failure or disturbances than because of repeated abortions and/or birth of a malformed child. Male carriers of CCR produce a high frequency of chromosomally abnormal spermatozoa due to the aberrant segregation of the rearranged chromosomes. The number of chromosomes and breakpoints involved in the rearrangement, the position of breakpoints, the relative size of the resultant chromosomes and the presence or absence of recombination inside the paired-rearranged segments are presumed to affect the fertility of the carrier. Testicular biopsy should not be performed in males with azoospermia. Intracytoplasmic sperm injection should not be proposed as a procedure for treating the infertility of CCR male carriers as a successful result is unlikely.

Familial 3-Way Balanced Translocation Causes 1q43→qter Loss and 10q25.2→qter Gain in a Severely Affected Male Toddler

“…According to our literature search, no other constitutional CCR involving chromosomes 1, 9, and 10 in the same instance has previously been described [e.g., Madan et al, 1997;Nguyen et al, 2015;Fukami et al, 2017]. In fact, CCRs specifically overlapping the breakpoints and entailing the same imbalance for one or the other chromosomes described herein are fairly infrequent (18 cases for chromosome 1, 0 cases for chromosome 9, and 3 cases for chromosome 10; ECARUCA).…”

The influence of balanced complex chromosomal rearrangements on preimplantation embryonic development potential and molecular karyotype

“…The first two involve translocations only, whereas exceptional CCR often includes other structural distortions, such as translocation, inversion, insertion, and others. Some CCR carriers often have growth deformities, mental retardation and congenital abnormalities [6][7][8][9] . Although many researchers have tried to explain the mechanism of CCR, it is still not clear.…”

Preimplantation genetic testing for balanced complex chromosomal rearrangement carriers by comprehensive chromosome screening

“…The first two involve translocations only, whereas exceptional CCRS often includes other structural distortions, such as translocation, inversion, insertion, and others. CCR carriers often have growth deformities, mental retardation and congenital abnormalities [6][7][8][9] . Although many researchers have tried to explain the mechanism of CCRs, it is still not clear.…”