The accurate evaluation of a marker chromosome has been limited during prenatal karyotyping. We proposed a method of step-by-step approach to evaluate the origin of a marker chromosome.
The routine chromosomal analysis showed 46,X,+mar. As the result of NOR banding, we supposed that the marker chromosome was less likely originated from acrocentric chromosomes. FISH analysis revealed Y centromere signal on marker chromosome, but Yq12 signal was not detected. Therefore the marker chromosome was identified as Y chromosome formed by deletion at Yq11.2.
CONCLUSION:
This study demonstrated that FISH and NOR banding technique is more effective method for a marker chromosome evaluation during prenatal karyotyping.