Elizabeth Baker1,2, Lyn Hinton1, David F. Callen1,3, Meryl Altree4, Angus Dobbie4, Helen J. Eyre1, Grant R. Sutherland1,3, Elizabeth Thompson4, Peter Thompson5, Erica Woollatt1, Eric Haan4
1Centre for Medical Genetics, Department of Cytogenetics and Molecular Genetics, Women's and Children's Hospital, Adelaide, Australia
2Department of Paediatrics, University of Adelaide, Adelaide, Australia
3Department of Molecular Biosciences, University of Adelaide, Adelaide, Australia
4South Australian Clinical Genetics Service, Women's and Children's Hospital, Adelaide, Australia
5University Hospital of Wales, Cardiff, Wales
Tóm tắt
AbstractCryptic subtelomeric chromosome anomalies have been recognized as a significant cause of dysmorphology and mental retardation. To determine whether the clinical cytogenetics laboratory should screen routinely for these aberrations, we have tested 250 patients with idiopathic mental retardation/developmental delay, either isolated (53) or associated with dysmorphic features and/or malformations in the absence of a recognizable syndrome (197). All had normal karyotypes at the 550–850 band level. Subtelomeric anomalies were found in 1/53 of the first group (1.9%) and 8/197 of the second group (4.1%). In one patient, two separate anomalies were present: a deletion (not inherited) and a duplication (inherited). It is possible that one of these 10 observed aberrations might represent a rare and previously unreported polymorphism and one a rare cross‐hybridization. Our study supports the proposition that cryptic subtelomeric rearrangements are a significant cause of idiopathic mental retardation/developmental delay, but both the diversity of the phenotypes of the positive cases and the wide diversity of their associated chromosome abnormalities emphasize the central problem for the clinical cytogenetics laboratory—that of choosing the most productive patient base for this useful diagnostic test. © 2002 Wiley‐Liss, Inc.
