Project description:Recurrent deletions on 15q13.3 have been identified as a predisposition to mental retardation, epilepsy and psychiatric disease. We report compound heterozygous deletions on 15q13.3 in one patients with severe encephalopathy and seizures. We analysed two independent patients with severe encephalopathy and seizures and found heterozygous deletions on 15q13.3 in both patients.
Project description:Profiling the genomic profiles of mental retardation patients. 13 mental retardation patients were selected for detection of genomic aberrations. Patient's DNA were hybridized against Promega control on Agilent G4426B arrays and scanned with the Agilent G2505B scanner.
Project description:Profiling the genomic profiles of mental retardation patients. 13 mental retardation patients were selected for detection of genomic aberrations. Overall design: Patient's DNA were hybridized against Promega control on Agilent G4426B arrays and scanned with the Agilent G2505B scanner.
Project description:In the study we present a multicenter study in which three European diagnostic centres assessed the use of Affymetrix Mapping 500k SNP arrays for molecular karyotyping in patients with mental retardation. Each centre tested DNA from 40 patients with unexplained mental retardation together with their parents. In addition, 38 DNA samples containing known submicroscopic copy number variations (CNVs) were run for validation purposes Keywords: genomic hybridisation Overall design: We performed a validation experiement where genomic DNA of 38 patients with mental retardation was hybridized onto Affymetrix' GeneChip 250K SNP (Nsp) arrays, and identified genome-wide CNVs. An application study was then performed where 40 trios from 3 different centres where hybrized and CNVs identified.
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 Overall design: See de Vries et al. Diagnostic genome profiling in mental retardation. American Journal of Human Genetics, vol 77: 606-616 (2005). In brief, each patient was hybridized in duplicate with label swap onto the tiling resolution BAC arrays. DNA from 72 parents was hybridized once to the same array in order to distinguish between disease-causing alterations and normal copy number variations. De novo alterations were validated by FISH and MLPA.
Project description:Mental retardation is more common in males than females in the population, assumed to be due to mutations on the X chromosome. The prevalence of the 24 genes identified to date is low and less common than expansions in FMR1, which cause Fragile X syndrome. Systematic screening of all other X linked genes in X linked families with mental retardation is currently not feasible in a clinical setting. The phenotypes of genes causing syndromic and non-syndromic mental retardation (NLGN3, NLGN4, RPS6KA3(RSK2), OPHN1, ATRX, SLC6A8, ARX, SYN1, AGTR2, MECP2, PQBP1, SMCX, and SLC16A2) are first discussed, as these may be the focus of more targeted mutation analysis. Secondly, the relative prevalence of genes causing only non-syndromic mental retardation (IL1RAPL1, TM4SF2, ZNF41, FTSJ1, DLG3, FACL4, PAK3, ARHGEF6, FMR2, and GDI) is summarised. Thirdly, the problem of recurrence risk where a molecular genetics diagnosis has not been made and what proportion of the male excess of mental retardation is due to monogenic disorders of the X chromosome are discussed.
Project description:Although autosomal forms of nonsyndromic mental retardation account for the majority of cases of mental retardation, the genes that are involved remain largely unknown. We sequenced the autosomal gene SYNGAP1, which encodes a ras GTPase-activating protein that is critical for cognition and synapse function, in 94 patients with nonsyndromic mental retardation. We identified de novo truncating mutations (K138X, R579X, and L813RfsX22) in three of these patients. In contrast, we observed no de novo or truncating mutations in SYNGAP1 in samples from 142 subjects with autism spectrum disorders, 143 subjects with schizophrenia, and 190 control subjects. These results indicate that SYNGAP1 disruption is a cause of autosomal dominant nonsyndromic mental retardation.
Project description:The cause of mental retardation in one-third to one-half of all affected individuals is unknown. Microscopically-detectable chromosomal abnormalities are the most frequent recognized cause, but gain or loss of chromosomal segments that are too small to be seen by conventional cytogenetic analysis has been found to be another important cause. Array-based methods offer a practical means of performing a high-resolution survey of the entire genome for submicroscopic copy number variants. We studied 100 children with idiopathic mental retardation and their parents using the Affymetrix GeneChip® Mapping 100K Assay and found de novo duplications as small as 1.1 Mb in three cases, de novo deletions as small as 178 kb in eight cases, and unsuspected mosaic trisomy 9 in another case. This technology can detect at least twice as many potentially pathogenic de novo copy number variants as conventional cytogenetic analysis in people with mental retardation. Experiment Overall Design: Using the Affymetrix GeneChip® Mapping 100K Assay we studied 100 trios that each included one child with idiopathic mental retardation (MR) and both of his/her unaffected biological parents. We also tested 10 unaffected siblings of the MR children from 10 of the above families. In addition, we analyzed 7 trios (child and both unaffected biological parents) as positive controls with previously identified chromosomal aberrations. Experiment Overall Design: Within each sample ID the four digit number refers to a family. Following this four digit family number, 'c' indicates child with MR, 'm' means unaffected mother, 'f' means unaffected father and 's' means unaffected sibling.
Project description:This SuperSeries is composed of the following subset Series: GSE29985: Identification by ChIP-on-Chip of ARX target genes, a transcription factor implicated in mental retardation and epilepsy GSE30190: Comparison of gene expression between Arx-transfected N2a cells and cells transfected by the corresponding empty vector Refer to individual Series
Project description:Mental retardation is a heterogeneous condition, affecting 1-3% of general population. In the last few years, several emerging clinical entities have been described, due to the advent of newest genetic techniques, such as array Comparative Genomic Hybridization. The detection of cryptic microdeletion/microduplication abnormalities has allowed genotype-phenotype correlations, delineating recognizable syndromic conditions that are herein reviewed. With the aim to provide to Paediatricians a combined clinical and genetic approach to the child with cognitive impairment, a practical diagnostic algorithm is also illustrated. The use of microarray platforms has further reduced the percentage of "idiopathic" forms of mental retardation, previously accounted for about half of total cases. We discussed the putative pathways at the basis of remaining "pure idiopathic" forms of mental retardation, highlighting possible environmental and epigenetic mechanisms as causes of altered cognition.