Prenatal Diagnosis of Yq Deletion by Cytogenetic and Fluorescence in Situ Hybridization / 대한주산의학회잡지

ABSTRACT

OBJECTIVE: 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. METHODS: A patient with 19 weeks of gestation was transferred to our hospital for karyotyping due to abnormal Triple test. Karyotyping of amniotic fluid was performed. NOR (nucleolar organizer region) banding and FISH (fluorescence in situ hybridization) using two types of sex chromosome probes: chromosome X alpha satellite probe (DXZI) & chromosome Y alpha satellite probe (DYZ3)(Cytocell, Bambury, UK) and CEP X/Y (Xp11.1-q11.1 CEP X alpha satellite & Yq12 CEP Y satellite III)(Vysis, IL, USA) were done. RESULTS: 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.