Detection of submicroscopic aberrations in patients with unexplained mental retardation by fluorescence in situ hybridization using multiple subtelomeric probes

Yao Shan Fan, Yang Zhang, Marsha Speevak, Sandra Farrell, Jack H. Jung, Victoria M. Siu

Research output: Contribution to journalArticle

54 Scopus citations


Purpose: To further assess the frequency of subtelomeric aberrations in a selected population and to examine the feasibility of a clinical testing. Methods: Patients were selected based on the following criteria: (1) mental retardation (IQ < 70) or developmental delay with dysmorphic features; (2) a normal karyotype at the level of resolution of 450 to 500 bands; and (3) exclusion of other possible etiologies by a full genetic assessment and relevant tests. Fluorescence in situ hybridization (FISH) was performed using multiple subtelomeric probes. Abnormal findings were confirmed by 24-color spectral karyotyping or FISH with a specific subtelomeric probe, and family studies were carried out to determine inheritance. Results: Clinically significant aberrations were detected in 6 of 150 proband patients (4%), while deletion of the 2q subtelomeric region appeared to be a common variant (6%). Conclusions: FISH with multiple subtelomeric probes is a valuable clinical test for establishing a definitive diagnosis for patients with unexplained mental retardation/developmental disorders.

Original languageEnglish (US)
Pages (from-to)416-421
Number of pages6
JournalGenetics in Medicine
Issue number6
StatePublished - Jan 1 2001
Externally publishedYes



  • Cryptic rearrangement
  • Developmental delay
  • Fluorescence in situ hybridization
  • Mental retardation
  • Multiple subtelomeric probes
  • Spectral karyotyping
  • Subtelomeric aberrations

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics

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