Molecular cytogenetic characterization of a familial balanced reciprocal translocation t(11;18) (q13.3; q23) associated with pregnancy wastage

A new male patient associated with a pregnancy wastage was detected in China. Cytogenetic analyses including G-banding, chromosome painting and observation of synaptonemal complexes (SCs) demonstrated that the pregnancy wastage was associated with a balanced reciprocal translocation t(11;18) (q13.3; q23). The proband was the carrier of the translocation and his karyotype was 46,XY,t(11;18)(11pter-->11q13.3:: 18q23-->18qter; 18pter-->18q23::11q13.3-->11qter). The pedigree was analyzed based on a G-banded karyotype of the nine familial members. The translocation chromosomes came from the proband's mother. The result of the SC observation in the proband showed that each of the spermatocytes displayed one quadrivalent during their pachytene stages. In the quadrivalents, there existed homologous and nonhomologous synapses and the latter occurred widely during early, middle and late pachytene stages. The reasons and genetic basis of the pregnancy wastage are discussed.