Clinical and cytogenetic manifestations of subtelomeric aberrations: Report of six cases.
BACKGROUND
Fluorescent subtelomeric probes for the 41 different subtelomeric regions (the p arms of the acrocentric chromosomes were excluded) have been developed over the last 10 years. These probes can detect deletions, duplications, and translocations in the gene-rich subtelomeric regions of human chromosomes, regions where crossing over frequently occurs and where a high number of abnormalities have been found. Recently, commercially produced probes have become available, which has led to the detection of subtelomeric abnormalities in 7.4% of patients with moderate to severe mental retardation (Knight et al., 1999).


METHODS
We evaluated 43 dysmorphic children with developmental delay and/or mental retardation of unknown etiology and/or autism who were previously assessed for chromosome abnormalities, metabolic disorders, or recognizable dysmorphic syndromes, all of which were ruled out. Of the 43 children tested, 6 (14%) were found to have subtelomeric aberrations.


CONCLUSIONS
We recommend that patients with dysmorphic features and mental retardation of unknown etiology who also have a normal standard chromosome analysis should have subtelomeric FISH testing performed earlier in their clinical workup.
Font-Montgomery
Esperanza
E
Department of Medical and Molecular Genetics, School of Medicine, Indiana University, Indianapolis, Indiana 46202-5251, USA. efontmon@iupui.edu
Weaver
David D
DD
Walsh
Laurence
L
Christensen
Celanie
C
Thurston
Virginia C
VC
D001321:Autistic Disorder / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D020732:Cytogenetic Analysis; D002658:Developmental Disabilities / Q000235:genetics*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D016615:Telomere / Q000235:genetics*