PRENATAL-DIAGNOSIS OF LOW-LEVEL TRISOMY-15 MOSAICISM - REVIEW OF THE LITERATURE

Low level chromosome mosaicism found at amniocentesis is problematic f or clinicians and patients. We report prenatal diagnosis of a fetus wi th a rare karyotype of 47,XX, + 15/46,XX. Second trimester amniocentes is was performed for advanced maternal age. Fetal ultrasound revealed a hypoplastic right ventricle and intrauterine growth retardation (IUG R). The rest of the fetal anatomy was within normal limits. A mosaic k aryotype of 47,XX, + 15/46,XX was observed. The couple interrupted the pregnancy at 19 weeks by dilation and suction evacuation. Careful eva luation of multiple pieces of fetal parts and placenta revealed one ab normal finding: a single umbilical artery. Cytogenetic metaphase and f luorescent in situ hybridization (FISH) interphase analyses of cells f rom fetal lung, heart, placenta, and skin revealed the presence of the trisomic line in all tissues. Molecular analysis demonstrated that th e origin of the extra chromosome 15 was maternal, the error most likel y occurred in meiosis I and the diploid line was of biparental inherit ance. This case report discusses the associated findings in this fetus and reviews the literature describing other cases of mosaic trisomy 1 5.