title: Co-occurrence of chromosome 22q11.2 microdeletion and trisomy 21 mosaicism.
abstract: This report describes a patient who had some phenotypic features of Down syndrome (DS) as well as severe conotruncal cardiac anomalies, including pulmonary atresia with ventricular septal defect (tetralogy of Fallot with pulmonary atresia), confluent pulmonary arteries, a large left-sided ductus arteriosus, left aortic arch, aberrant right subclavian artery, and secundum atrial septal defect. Cytogenetic and fluorescence in situ hybridization (FISH) analysis was carried out on peripheral blood lymphocytes and skin fibroblasts using probes specific for the chromosomal loci 21q22.13 to 21q22.2 and locus 22q11.2. This revealed 47,XX+21/46,XX mosaicism at a rate of 15:85 and the micro-deletion 22q11.2 (del22q11.2). Some patients'congenital cardiac anomalies are atypical for the type of mosaicism or aneuploidy. The case suggests that association of del22q11.2 should be considered in patients with chromosomal mosaicism or aneuploidy who also have particular conotruncal cardiac defects.
authors.affiliation: Department of Pediatrics, Baskent University Faculty of Medicine, Ankara, Turkey. muratder@superonline.com
authors.forename: Murat
authors.initials: M
authors.lastname: Derbent
authors.forename: Arda
authors.initials: A
authors.lastname: Saygili
authors.forename: Zerrin
authors.initials: Z
authors.lastname: Yilmaz
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kervancioğlu
authors.forename: Sevim
authors.initials: S
authors.lastname: Balci
authors.forename: Kursat
authors.initials: K
authors.lastname: Tokel
mesh_terms: D002892:Chromosomes, Human, Pair 22; D004314:Down Syndrome; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D008297:Male; D009030:Mosaicism