title: Cytogenetic molecular delineation of a terminal 18q deletion suggesting neo-telomere formation.
abstract: Deletion of the long arm of chromosome 18 is one of the most common segmental aneusomies compatible with life and usually involves a deletion of the terminal chromosomal region. However, the mechanisms implicated in the stabilization of terminal deletions are not well understood. In this study, we analyzed a girl with moderate mental retardation who had a cytogenetically visible terminal 18q deletion. In order to characterize the breakpoint in the terminal 18q region, we used fluorescence In situ hybridization (FISH) with bacterial artificial chromosomes (BACs) and pan-telomeric probes and also the array technique based on comparative genomic hybridization (array-CGH). FISH with pan-telomeric probes revealed no signal in the terminal region of the deleted chromosome, indicating the absence of normal telomere repeat (TTAGGG)n sequences in 18q. We suggest that neo-telomere formation by chromosome healing was involved in the repair and stabilization of this terminal deletion.
authors.affiliation: Department of Morphology and Genetics, Universidade Federal de São Paulo, São, Paulo, SP, Brazil. lesliekulik@hc.usp.br
authors.forename: Leslie Domenici
authors.initials: LD
authors.lastname: Kulikowski
authors.forename: Maisa
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Fernanda Teixeira
authors.initials: FT
authors.lastname: da Silva Bellucco
authors.forename: Sintia Iole Nogueira
authors.initials: SI
authors.lastname: Belangero
authors.forename: Denise Maria
authors.initials: DM
authors.lastname: Christofolini
authors.forename: Ade Nubia Xavier
authors.initials: AN
authors.lastname: Pacanaro
authors.forename: Adriana
authors.initials: A
authors.lastname: Bortolai
authors.forename: Marilia de Arruda Cardoso
authors.initials: Mde A
authors.lastname: Smith
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Squire
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Melaragno
mesh_terms: D000293:Adolescent; D002872:Chromosome Deletion; D002887:Chromosomes, Human, Pair 18; D055028:Comparative Genomic Hybridization / Q000379:methods*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008607:Intellectual Disability / Q000235:genetics; D007621:Karyotyping; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D016615:Telomere / Q000235:genetics* / Q000378:metabolism