title: Pure and complete trisomy 18p due to a supernumerary marker chromosome associated with moderate mental retardation.
abstract: Trisomy for the short arm of chromosome 18 or trisomy 18p, is rarely described. We report on a 13-year-old boy with minor facial anomalies, mental retardation, bilateral cryptorchidism associated with a de novo supernumerary marker chromosome (SMC). Using fluorescence in situ hybridization and comparative genomic hybridization analyses, this SMC corresponded to the p arm of chromosome 18 associated with a centromere of either chromosome 13 or 21 and nucleolus organizing regions (NORs). We report here the first case of a pure and complete trisomy 18p due to a SMC. This report and review of literature confirm that the main phenotypic anomaly associated with trisomy 18p is moderate mental retardation.
authors.affiliation: Service d'Histologie Embryologie Cytogénétique, INSERM U782, Hôpital Antoine Béclère, APHP, Université Paris Sud, Clamart, France. philippe.mabboux@abc.aphp.fr
authors.forename: P
authors.initials: P
authors.lastname: Mabboux
authors.forename: S
authors.initials: S
authors.lastname: Brisset
authors.forename: A
authors.initials: A
authors.lastname: Aboura
authors.forename: D
authors.initials: D
authors.lastname: Pineau
authors.forename: V
authors.initials: V
authors.lastname: Koubi
authors.forename: S
authors.initials: S
authors.lastname: Joannidis
authors.forename: P
authors.initials: P
authors.lastname: Labrune
authors.forename: G
authors.initials: G
authors.lastname: Tachdjian
mesh_terms: D000293:Adolescent; D002648:Child; D002887:Chromosomes, Human, Pair 18; D020732:Cytogenetic Analysis; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D014314:Trisomy