Project description:Application of CGH-array for the detection of genomic rearrangements responsible for sindromic mental retardation of unknown cause
| PRJNA264096 | ENA
Project description:Application of CGH-array and SNP-array for the detection of genomic rearrangements responsible for sindromic mental retardation of unknown cause
Project description:Non-syndromic mental retardation is one of the most important unresolved problems in genetic health care. Autosomal forms are far more common than X-linked ones, but in contrast to the latter, they are still largely unexplored. Here we report on a complex mutation in the ionotropic glutamate receptor 6 gene (GRIK2, GLUR6), which co-segregates with moderate to severe non-syndromic autosomal recessive mental retardation in a large consanguineous Iranian family1. The predicted gene product lacks the first ligand-binding domain, the two adjacent transmembrane domains and the putative pore-forming loop of the GLUK6 protein, suggesting a complete loss of function, which is supported by electrophysiological data. This finding provides the first irrefutable proof that GLUK6 is indispensable for higher brain functions in man, and future studies of this and other ionotropic kainate receptors will shed more light on the pathophysiology of mental retardation. Keywords: array CGH
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. Keywords: mental retardation, trio analysis, copy number variant, CNV, chromosome aberration, array CGH
Project description:Mutations in KDM5C, (previously named SMCX or JARID1C) a gene that encodes a transcriptional regulator with histone-demethylase activity specific for di- and tri-methylated H3K4, are a comparatively frequent cause of non-syndromic X-linked mental retardation (NS-XLMR). Specific transcriptional targets of KDM5C, however, are still unknown and the effects of KDM5C deficiency on gene expression have not yet been investigated. Here we present the results of gene expression profiling performed on lymphoblastoid cell lines as well as blood from patients with mutations in KDM5C. Using whole genome expression arrays and QRT-PCR we identified several genes, including CMKOR1, JARID1B and KIAA0469 that were consistently deregulated in both tissues. These findings shed light on the patho-mechanisms underlying mental retardation and may have implications for future diagnostics of this heterogeneous disorder. We compared the mRNA expression of a patient lymphoblastoid cell line deficient for KDM5C with that of three controls to identify genes that are deregulated in the patient cell line.
Project description:Mutations in KDM5C, (previously named SMCX or JARID1C) a gene that encodes a transcriptional regulator with histone-demethylase activity specific for di- and tri-methylated H3K4, are a comparatively frequent cause of non-syndromic X-linked mental retardation (NS-XLMR). Specific transcriptional targets of KDM5C, however, are still unknown and the effects of KDM5C deficiency on gene expression have not yet been investigated. Here we present the results of gene expression profiling performed on lymphoblastoid cell lines as well as blood from patients with mutations in KDM5C. Using whole genome expression arrays and QRT-PCR we identified several genes, including CMKOR1, JARID1B and KIAA0469 that were consistently deregulated in both tissues. These findings shed light on the patho-mechanisms underlying mental retardation and may have implications for future diagnostics of this heterogeneous disorder.
Project description:Profiling the genomic profiles of mental retardation patients. 13 mental retardation patients were selected for detection of genomic aberrations.
2009-12-16 | GSE19457 | GEO
Project description:Houge type of X-linked syndromic mental retardation
Project description:We report a recurrent microdeletion syndrome causing mental retardation, epilepsy and variable facial and digital dysmorphisms. We describe nine patients, including six probands; two with de novo deletions, two who inherited the deletion from an affected parent, and two with unknown inheritance. The proximal breakpoint of the largest deletion is contiguous with breakpoint 3 (BP3) of the Prader-Willi/Angelman region extending 3.95 Mb distally to BP5. A smaller 1.5 Mb deletion has proximal breakpoint within the larger deletion (BP4) and shares the same distal BP5. This recurrent 1.5 Mb deletion contains six genes, including a candidate gene for epilepsy (CHRNA7) that is likely responsible for the observed seizure phenotype. The BP4-BP5 region undergoes frequent inversion, suggesting a possible link between this inversion polymorphism and recurrent deletion. The frequency of these microdeletions in mental retardation cases is ~0.3% (6/2082 tested), a prevalence comparable to that of the Williams, Angelman, and Prader-Willi syndromes. Keywords: microdeletion, genomic disorder, mental retardation, epilepsy Patients were intially screened by BAC array CGH (n=290) or qPCR (n=1040). Patients with potential 15q13 deletions were then analyzed on a custom oligonucleotide array targeted to the 15q13 region, results of which are shown here.