title: Clinical, cytogenetic, and molecular findings in a patient with a 46,XX,del(18)(q22)/46,XX,idic(18)(q22) karyotype.
abstract: Pseudoisodicentric or asymmetrical dicentric chromosomes 18 are rare findings in clinical cytogenetics. So far, only 8 patients with breakpoints in 18q have been reported and in none of them breakpoints were narrowed down to the molecular level. Here, we describe a 17 months old girl with a perimembranous ventricular septal defect, cleft palate, and minor dysmorphism including hypertelorism, flat nose, frontal bossing and low set ears as well as mosaicism for a cell line with a pseudoisodicentric chromosome 18q and a second cell line with a terminal deletion of 11 Mb in 18q22.2→qter. SNP-array investigation revealed a symmetric breakpoint in 18q22.2 and most likely postzygotic formation from the maternal chromosome 18. Clinical findings in all patients reported so far as well as in the patient presented here were in part overlapping with the clinical phenotypes of trisomy 18 and partial monosomy 18q.
authors.affiliation: Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria.
authors.forename: Olaf
authors.initials: O
authors.lastname: Rittinger
authors.affiliation: Division of Human Genetics, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Birgit
authors.initials: B
authors.lastname: Krabichler
authors.affiliation: Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg, Austria.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Kronberger
authors.affiliation: Division of Human Genetics, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: DieterKotzot@gmx.de.
authors.forename: Dieter
authors.initials: D
authors.lastname: Kotzot
mesh_terms: D002872:Chromosome Deletion; D058674:Chromosome Duplication; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D002972:Cleft Palate / Q000175:diagnosis / Q000235:genetics*; D019465:Craniofacial Abnormalities / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006345:Heart Septal Defects, Ventricular / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D007223:Infant; D059785:Karyotype; D009030:Mosaicism; D013577:Syndrome
keywords: Chromosomal rearrangements; Isochromosomes; Parental origin; SNP-array