Small supernumerary marker chromosomes derived from chromosomes 6 and 20 in a woman with recurrent spontaneous abortions

Abstract

In this report, we describe a case of multiple small supernumerary marker chromosomes (sSMC) presenting with recurrent abortions. Peripheral blood lymphocytes of a young, healthy and non-consanguineous couple who asked for genetic evaluation after two spontaneous miscarriages were obtained for karyotypes. Lymphocytes of the woman were analyzed by FISH techniques and DNA was extracted and used for array CGH investigation. Karyotyping revealed 48,XX,+2mar[24]/47,XX,+mar[5]/46,XX[3] for the woman and 46,XY for her husband. FISH analysis showed that the two sSMC consisted of chromosomes 6 and 20. Array CGH analysis showed gains of the 6p11.2q12 (9 Mb) and 20 p11.21 (3.3 Mb) chromosomal regions with a total of 42 genes present on both sSMC. Our findings support also the hypothesis that the modification of the expression of some genes involved in embryo implantation, like THBD gene, could be responsible in the recurrent abortions. This report underpins the necessity of array CGH for characterizing precisely sSMC and helping in genotype-phenotype correlations. Furthermore, a literature review on sSMC is included.