A review of characteristic features identifying balanced chromosomal translocations with increased potential for 3:1 meiotic segregation

A carrier of a balanced translocation is at risk for abnormal chromosome segregation during the meiotic events of gamete formation. During meiosis all four chromosomes, both derivatives and their normal homologs, pair together forming a four-chromosome structure or quadrivalent. Segregation of the quadrivalent occurs in several iterations. Most typically, the outcome of this segregation results in 2 of the quadrivalent chromosomes per gamete in either an alternate, adjacent-1 or adjacent-2 configuration.