A Novel de novo Balanced Reciprocal Translocation t(18;22) Associated with Recurrent Miscarriages: A Case Report

Abstract

Background: Recurrent miscarriage is a major concern in the couples with reproductive problems. The chromosomal abnormalities, mainly balanced rearrangements are reported in variable phenotypes and the prevalence of them is 2-8% in such couples.

Case presentation: In this study, the clinical, cytogenetic and molecular cytogenetic evaluations were performed on a couple with RM. The cytogenetic analysis of the husband revealed a balanced reciprocal translocation of t(18;22)(q21.1;q12) whereas wife had a normal karyotype of 46,XX. Further spectral karyotyping was performed to rule out the involvement of any other chromosomal aberrations present in the genome. Additional whole chromosome paint FISH (Fluorescence in situ hybridization) with paint probes 18 and 22 confirmed the translocation.

Conclusion: To our knowledge, this is the first report of a novel (18;22) translocation with unique breakpoints and their association with RM. The reciprocal translocations provide a good opportunity for the identification of disease associated genes. However, in recurrent miscarriages, most of them do not disrupt any gene at the breakpoint but can lead to unbalanced gametes and hence poor reproductive outcome like RM or birth of a child with malformations and intellectual disability. The translocation breakpoints might be risk factors for RM. Moreover, the impact of the balanced translocations in association with RM is discussed in this report.

Keywords: Balanced translocation; FISH; GTG banding; Recurrent miscarriages; SKY.

Figure 1

The chromosomes involved in the translocation t(18;22)(q21.1;q12) of the illustrated case. A. The GTG banded karyogram showing the translocation breakpoint regions. B. The partial ideogram showing normal chromosome 18 in red and normal 22 in green and both derivative 18 and derivative 22 in red and green

Figure 2

SKY on the lymphocyte metaphase showing the representative karyotypes illustrating the display colours on the left and the classification colours on the right. In the center, there are the DAPI band images

Figure 3

WCP FISH on the metaphase spreads of the proband. The normal chromosome 18 is in red and the normal 22 in green. Derivative 18 and derivative 22 are shown both in red and green