title: Identification of chromosome abnormalities in subtelomeric regions by microarray analysis: a study of 5,380 cases.
abstract: Subtelomeric imbalances are a significant cause of congenital disorders. Screening for these abnormalities has traditionally utilized GTG-banding analysis, fluorescence in situ hybridization (FISH) assays, and multiplex ligation-dependent probe amplification. Microarray-based comparative genomic hybridization (array-CGH) is a relatively new technology that can identify microscopic and submicroscopic chromosomal imbalances. It has been proposed that an array with extended coverage at subtelomeric regions could characterize subtelomeric aberrations more efficiently in a single experiment. The targeted arrays for chromosome microarray analysis (CMA), developed by Baylor College of Medicine, have on average 12 BAC/PAC clones covering 10 Mb of each of the 41 subtelomeric regions. We screened 5,380 consecutive clinical patients using CMA. The most common reasons for referral included developmental delay (DD), and/or mental retardation (MR), dysmorphic features (DF), multiple congenital anomalies (MCA), seizure disorders (SD), and autistic, or other behavioral abnormalities. We found pathogenic rearrangements at subtelomeric regions in 236 patients (4.4%). Among these patients, 103 had a deletion, 58 had a duplication, 44 had an unbalanced translocation, and 31 had a complex rearrangement. The detection rates varied among patients with a normal karyotype analysis (2.98%), with an abnormal karyotype analysis (43.4%), and with an unavailable or no karyotype analysis (3.16%). Six patients out of 278 with a prior normal subtelomere-FISH analysis showed an abnormality including an interstitial deletion, two terminal deletions, two interstitial duplications, and a terminal duplication. In conclusion, genomic imbalances at subtelomeric regions contribute significantly to congenital disorders. Targeted array-CGH with extended coverage (up to 10 Mb) of subtelomeric regions will enhance the detection of subtelomeric imbalances, especially for submicroscopic imbalances.
authors.affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Lina
authors.initials: L
authors.lastname: Shao
authors.forename: Chad A
authors.initials: CA
authors.lastname: Shaw
authors.forename: Xin-Yan
authors.initials: XY
authors.lastname: Lu
authors.forename: Trilochan
authors.initials: T
authors.lastname: Sahoo
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Bacino
authors.forename: Seema R
authors.initials: SR
authors.lastname: Lalani
authors.forename: Pawel
authors.initials: P
authors.lastname: Stankiewicz
authors.forename: Svetlana A
authors.initials: SA
authors.lastname: Yatsenko
authors.forename: Yinfeng
authors.initials: Y
authors.lastname: Li
authors.forename: Sarah
authors.initials: S
authors.lastname: Neill
authors.forename: Amber N
authors.initials: AN
authors.lastname: Pursley
authors.forename: A Craig
authors.initials: AC
authors.lastname: Chinault
authors.forename: Ankita
authors.initials: A
authors.lastname: Patel
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Beaudet
authors.forename: James R
authors.initials: JR
authors.lastname: Lupski
authors.forename: Sau W
authors.initials: SW
authors.lastname: Cheung
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D001321:Autistic Disorder / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D025063:Chromosome Disorders / Q000235:genetics*; D002658:Developmental Disabilities / Q000235:genetics; D018628:Gene Dosage; D020440:Gene Duplication; D015894:Genome, Human; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics; D007621:Karyotyping; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D017384:Sequence Deletion; D016615:Telomere / Q000235:genetics*