Cytogenetic molecular delineation of a terminal 18q deletion suggesting neo-telomere formation.
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.
Kulikowski
Leslie Domenici
LD
Department of Morphology and Genetics, Universidade Federal de São Paulo, São, Paulo, SP, Brazil. lesliekulik@hc.usp.br
Yoshimoto
Maisa
M
da Silva Bellucco
Fernanda Teixeira
FT
Belangero
Sintia Iole Nogueira
SI
Christofolini
Denise Maria
DM
Pacanaro
Ade Nubia Xavier
AN
Bortolai
Adriana
A
Smith
Marilia de Arruda Cardoso
Mde A
Squire
Jeremy A
JA
Melaragno
Maria Isabel
MI
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