Study of two cases of prenatally detected small supernumerary marker chromosomes

Abstract To determine the origin of two prenatally detected small supernumerary marker chromosomes (sSMCs). The sSMCs were analyzed with combined G-banding, C-banding, fluorescence in situ hybridization (FISH), and single nucleotide polymorphisms array (SNP-array) techniques. In case 1, G-banding analysis has identified a 47,XY,+mar karyotype. Affymetrix CytoScan 750K Array scan has suggested arr 15q11.2q12(22 770 421-26 604 587)?, while FISH analysis suggested 47,XN,+mar.ish i(15)(q12)(D15Z1+,SNRPN++,PML-). In case 2, G-banding analysis has suggested 46,X,+mar/46,XY, FISH analysis showed two SRY hybridization signals, indicating 46,X,i(Y)(p10)/46,XY. Multiple techniques needed be applied for verification of the origin of sSMCs identified in prenatal diagnosis.