title: Two cases of tetrasomy 9p syndrome with tissue limited mosaicism.
abstract: Tetrasomy of short arm of chromosome 9 constitutes a clinically recognizable chromosomal syndrome. Isochromosome 9p shows a strong propensity to tissue-limited mosaicism. It occurs predominantly in peripheral blood cultures, often at a lower frequency or even absent in skin, amniotic fluid or chorionic villous cell cultures. Tissue-limited nature of mosaicism may render prenatal detection of this condition very difficult. Herein, we report two new cases of mosaic tetrasomy 9p. Conventional cytogenetics (CC) and FISH studies demonstrated a differential expression of the mosaicism in several tissues. We review the literature and discuss the implications of these findings in cytogenetic prenatal diagnosis.
authors.affiliation: Departament de Citogenética, General Lab-Laboratoris d'Anàlisis, C/Londres no. 45, 08036 Barcelona, Spain. elilloveras@hotmail.com
authors.forename: Elisabet
authors.initials: E
authors.lastname: Lloveras
authors.forename: C
authors.initials: C
authors.lastname: Pérez
authors.forename: F
authors.initials: F
authors.lastname: Solé
authors.forename: L
authors.initials: L
authors.lastname: Zamora
authors.forename: A
authors.initials: A
authors.lastname: Lladonosa
authors.forename: B
authors.initials: B
authors.lastname: Espinet
authors.forename: E
authors.initials: E
authors.lastname: Silvestre
authors.forename: J
authors.initials: J
authors.lastname: Serra
authors.forename: T
authors.initials: T
authors.lastname: Vendrell
authors.forename: B
authors.initials: B
authors.lastname: Fernández
authors.forename: M
authors.initials: M
authors.lastname: Salido
authors.forename: A
authors.initials: A
authors.lastname: Plaja
mesh_terms: D000782:Aneuploidy; D002675:Child, Preschool; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000235:genetics; D002899:Chromosomes, Human, Pair 9; D020732:Cytogenetic Analysis; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018404:Isochromosomes / Q000235:genetics; D008297:Male; D009030:Mosaicism / Q000235:genetics* / Q000473:pathology; D011296:Prenatal Diagnosis; D013577:Syndrome