Prenatal diagnosis and molecular cytogenetic analysis of a de novo isodicentric chromosome 18

ABSTRACT

Isodicentric chromosome 18 [idic[18]] is rare structural aberration. We report on a prenatal case described by conventional and molecular cytogenetic analyses. The sonography at 24 weeks of gestation revealed multiple fetal anomalies; radial aplasia and ventricular septal defect were significant features. Routine karyotyping showed a derivative chromosome replacing one normal chromosome 18. the parental karyotypes were normal, indicating that the derivative chromosome was de novo. Array comparative genomic hybridization [array-CGH] revealed 18p11.21[right wards arrow] qter]. Fluorescent in situ hybridization [FISH] confirmed that the derivative chromosome was idic[18]. Our report describes a rare isodicentric chromosome 18 and demonstrates that array-CGH is a useful complementary tool to cytogenetic analysis for reliable identifying derivative chromosome