Prenatal diagnosis and molecular cytogenetic characterization of an interstitial deletion of 18q12.1-q12.3 encompassing DTNA, CELF4 and SETBP1

Abstract

ObjectiveWe present prenatal diagnosis and molecular cytogenetic characterization of an interstitial deletion of 18q12.1-q12.3. Case reportA 35-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XX,del(18)(q12.1q12.3). The fetal ultrasound was unremarkable. The woman underwent repeat amniocentesis at 20 weeks of gestation. Array comparative genomic hybridization (aCGH) using uncultured amniocytes revealed a 10.76-Mb interstitial deletion 18q12.1-q12.3 or arr 18q12.1q12.3 (31,944,347–42,704,784) × 1.0 encompassing 19 Online Mendelian Inheritance of in Man (OMIM) genes including DTNA, CELF4 and SETBP1. Metaphase fluorescence in situ hybridization analysis on cultured amniocytes confirmed an 18q proximal interstitial deletion. The parental karyotypes were normal. Polymorphic DNA marker analysis determined a paternal origin of the deletion. The pregnancy was subsequently terminated at 24 weeks of gestation, and a 650-g fetus was delivered with characteristic facial dysmorphism. ConclusionaCGH analysis and polymorphic DNA marker analysis at amniocentesis are useful for determination of the deleted genes and the parental origin of the de novo deletion, and the acquired information is helpful for genetic counseling.