Project description:Abnormalities in DNA copy number are frequently found in patients with multiple anomaly syndromes and mental retardation. Array-CGH is a high resolution whole-genome technology which improves detection of submicroscopic aberrations underlying these syndromes. Eight patients with mental disability, multiple congenital anomalies and dysmorphic features were screened for submicroscopic chromosomal imbalances using the GenoSensor Array 300 Chip. Subtelomeric aberrations previously detected by FISH analysis were confirmed in two patients, and accurate diagnosis was provided in two previously undiagnosed complex cases. Microdeletions at 15q11.2-q13 in a newborn with hypotonia, cryptorchidsm and hypopigmentation were detected with few discrepancies between the array results and FISH analysis. Contiguous microdeletion of GSCL, HIRA and TBX1 genes at 22q11.2 was identified in a previously undiagnosed boy with an unusual presentation of the VCF/DiGeorge spectrum. In a newborn with aniridia, a borderline false negative WT1 deletion was observed, most probably because of differences between the size of the genomic deletion and the microarray probe. A false positive rate of 0.2% was calculated for clone-by-clone analysis, while the per patient false positive rate was 20%. Array-based CGH is a powerful tool for the rapid and accurate detection of genetic disorders associated with copy number abnormalities, and can significantly improve clinical genetic diagnosis and care. Keywords: comparative genome hybridization (CGH)
Project description:This series represent the data set belonging to the publication by de Vries et al. Diagnostic genome profiling in mental retardation. American Journal of Human Genetics, vol 77: 606-616 (2005). In this study 100 patients with unexplained mental retardation were analyzed for DNA copy-number changes using a tiling-resolution genomewide microarray containing 32,447 BACs. Keywords: CGH
Project description:Mental retardation (MR) is a non-progressive cognitive impairment affecting 2 to 3% of the Western population. So far, point mutations and subtle deletions and insertions have been shown to represent only a proportion (<40%) of genetic causes underlying X-linked mental retardation (XLMR). We have screened a subset of 300 presumable X-linked families by X chromosome-specific array-CGH and identified 6 families with overlapping microduplications at Xp11.22 containing two candidate genes; both of which showed overexpression in the affected individuals. Array-CGH data revealed aberrant Cy5/Cy3 log2 ratios for different but overlapping sets of clones indicating varying sizes of these duplications in the different families. X chromosome-specific array-CGH performed for probands of families A, FAM3, B, MRX17, C, MRX31, and D, A057, revealing the duplications at Xp11.22. DNA from two unrelated MR patients were differentially labeled and co-hybridized onto the X-array. The patients with duplications were hybridized in Cy5 against unrelated MR patients, named Pat XY1-6, in the Cy3 channel.
Project description:In this study 405 patients with unexplained mental retardation and 89 unaffected parents were analyzed for DNA copy-number changes using a tiling-resolution genomewide microarray containing 32,447 BACs. This series contains 367 slides from 315 individuals previously not reported, plus an additional 239 slides from 179 individuals previously reported in the series GSE3191. Keywords: array CGH
Project description:Mental retardation (MR) is a non-progressive cognitive impairment affecting 2 to 3% of the Western population. So far, point mutations and subtle deletions and insertions have been shown to represent only a proportion (<40%) of genetic causes underlying X-linked mental retardation (XLMR). We have screened a subset of 300 presumable X-linked families by X chromosome-specific array-CGH and identified 6 families with overlapping microduplications at Xp11.22 containing two candidate genes; both of which showed overexpression in the affected individuals. Array-CGH data revealed aberrant Cy5/Cy3 log2 ratios for different but overlapping sets of clones indicating varying sizes of these duplications in the different families. Keywords: comparative genomic hybridization
Project description:This series represents the data set described in the publication “Impact of low copy repeats on the generation of balanced and unbalanced chromosomal aberrations in mental retardation” by Erdogan et al. (Cytogenetics and Genome Research, accepted). Keywords: array CGH