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: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:We report a deletion on 11q13.3-q13.4 in one patients with severe mental retardation. We analyzed a patient with mental retardation and the related parents with a whole genome SNP Array.
Project description:Profiling the genomic profiles of mental retardation patients. 13 mental retardation patients were selected for detection of genomic aberrations.
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: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: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.
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.