Prenatal molecular cytogenetic analysis of a mild dysmorphic fetus with a huge unbalance karyotype involving partial 9p deletion and partial 18q duplication

Abstract

Partial 9p deletion syndrome and partial 18q duplication syndrome each have distinct clinical features. We describe the prenatal molecular cytogenetic analysis of a de novo unbalanced karyotype with deletion of 9p23-pter and duplication of 18q12.2-qter in a mild dysmorphic female fetus. Fetal ultrasonography was performed and detailed karyotype analyses were conducted using a combination of G-banding, SKY analysis and FISH with chromosome arm specific sub-telomeric DNA probes and chromosomal region specific BAC clone probes. The fetal sonography and fetal echocardiography at 17 weeks’ gestation did not reveal any anomaly while the fetus had a large unbalance karyotype of 46,XX,der(9)t(9;18) (p23;q12.2) de novo. Its external phenotype at 21 weeks appeared to have some mild dysmorphic features including hypertelorism, low-set ears, micrognathia/retrognathia, clenched hands and rocker bottom feet. These dysmorphic features are seen in the Edward syndrome but with milder degrees.