Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 2-8% of patients with mental retardation, small copy number changes in the subtelomeric region are thought to be the underlying cause. As detection of these genomic rearrangements is labour intensive using FISH, we constructed and validated a high-density BAC/PAC array covering the first 5 Mb of all subtelomeric regions and applied it in our routine screening of patients with idiopathic mental retardation for submicroscopic telomeric rearrangements. The present study shows the efficiency of this comprehensive subtelomere array in detecting terminal deletions and duplications but also small interstitial subtelomeric rearrangements, starting from small amounts of DNA. With our array, the size of the affected segments, at least those smaller than 5 Mb, can be determined simultaneously in the same experiment. In the first 100 patient samples analysed in our diagnostic practice by the use of this comprehensive telomere array, we found three patients with deletions in 3p, 10q and 15q, respectively, four patients with duplications in 9p, 12p, 21q and Xp, respectively, and one patient with a del 6q/dup 16q. The patients with del 3p and 10q and dup 12p had interstitial rearrangements that would have been missed with techniques using one probe per subtelomeric region chosen close to the telomere.
 ...
PMID:Application of a comprehensive subtelomere array in clinical diagnosis of mental retardation. 1617 21

High-resolution array CGH utilizing sets of overlapping BAC and PAC clones ("tiling path") covering the whole genome is a powerful novel tool for fast detection of submicroscopic chromosome deletions or duplications. We describe the successful application of a submegabase resolution whole genome "tiling path" BAC array to confirm and characterize a de novo interstitial deletion of chromosome 15. The deletion has a size of 5.3 Mb and is located within chromosome band 15q14, distal to the Prader-Willi/Angelman region. The affected girl had a heart defect, cleft palate, recurrent infections, and developmental delay. In contrast to GTG banding, array CGH determined the exact number of deleted genes and thus allowed the identification of candidate genes for cleft palate (GREM1, CX36, MEIS2), congenital heart defect (ACTC, GREM1, CX36, MEIS2), and mental retardation (ARHGAP11A, CHRNA7, CHRM5).
 ...
PMID:Characterization of a 5.3 Mb deletion in 15q14 by comparative genomic hybridization using a whole genome "tiling path" BAC array in a girl with heart defect, cleft palate, and developmental delay. 1716 32

The clinical implementation of array comparative genomic hybridization has revolutionized the diagnosis of patients with syndromic or nonsyndromic mental retardation. Multiple studies of hundreds of patients with idiopathic mental retardation, and normal karyotype and/or subtelomeric testing using genome-wide microarray platforms with approximately 2000 to >30,000 (tiling-path) interrogating BAC/PAC probes have detected chromosome abnormalities in up to 17% of cases. Surprisingly, some of the pathogenic changes are mosaic and not detectable in conventional karyotyping. Commercially available genome-wide microarrays with >300,000 synthesized oligonucleotide probes enable higher resolution and sensitivity and will probably replace the BAC/PAC arrays in clinical laboratories.
 ...
PMID:Use of array CGH in the evaluation of dysmorphology, malformations, developmental delay, and idiopathic mental retardation. 1746 74

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.
 ...
PMID:Identification of chromosome abnormalities in subtelomeric regions by microarray analysis: a study of 5,380 cases. 1866 43


<< Previous 1 2 3