Unusual prenatal case with multiple marker chromosomes

Abstract

Here we report a prenatal case with clonally present different marker chromosomes with GTG banding in multiple cell lines cultured from amniotic cells obtained at 18 weeks of gestation. The amniocentesis was performed because of an increased risk for Down syndrome based on a first trimester screening test but without ultrasonographically detected features. Fetal karyotype was 47õ50,XX,+mar1, +mar2,+mar3[cp50]. CBG and NOR banding showed that all markers had one centromere and no satellites. One of the markers had an unstained region on both arms with CBG banding. Both parents were found to have normal karyotypes. FISH analysis by multiprobe (cytocell) revealed marker chromosomes derived from chromosome 3, 7, and 8. The pregnancy was terminated after genetic counselling. The Fetus presented a small ventricular septal defect, cliteromegaly, and pulmonary segmental defects on autopsy examination following termination at 22 weeks of gestational age. Cytogenetic analysis of skin fibroblasts confirmed these results.