Project description:Preterm birth is the major cause of newborn and infant mortality affecting nearly one in every ten live births. This study was designed to develop an epigenetic biomarker for susceptibility of preterm birth using buccal cells from the mother, father, and child (triads). MeDIP-seq was used to identify differential DNA methylation regions (DMRs) using a comparison of control term birth versus preterm birth triads. Epigenetic DMR associations with preterm birth were identified for both the mother and father that were distinct and suggest potential epigenetic contributions from both parents. The mother (165 DMRs) and female child (136 DMRs) at p<1e-04 had the highest number of DMRs and were highly similar suggesting potential epigenetic inheritance of the epimutations. The male child had negligible DMR associations. The DMR associated genes for each group involve previously identified preterm birth associated genes.
Project description:We designed a microarray to test at exonic resolution for genomic imbalance for genes representative of all known chromosomal microdeletion/microduplication syndromes, all known causative genes for ID, all known genes encoding glutamate receptors and their known encoding proteins and all known genes encoding proteins with epigenetic regulatory function. We found 36 de novo copy number variants affecting 35 children in this study. 167 trios, each comprising an affected child and both its normal parents were analyzed by conducting two comparative hybridizations; child vs. mother and child vs. father, and only selecting a CNV if it appeared in both hybridizations, i.e., was de novo. De novo CNVs were independantly validated using quantitative PCR.
Project description:Clinical laboratories are adopting array comparative genomic hybridization (AGH) as a standard clinical test. A number of whole genome AGH systems are available, but little is known about the comparative performance in a clinical context. We prospectively studied 30 children with idiopathic MR and both unaffected parents of each child using Affymetrix 500K GeneChip SNP arrays, Agilent Human Genome 244K oligonucleotide arrays and NimbleGen 385K Whole-Genome oligonucleotide arrays. We determined whether CNVs called on these platforms were detected by Illumina Hap550 beadchips or SMRT 32K BAC whole genome tiling arrays and tested 15 of the 30 trios on Affymetrix 6.0 SNP array. The Affymetrix 500K, Agilent and NimbleGen platforms identified 3061 autosomal and 117 X chromosome CNVs in 30 trios. 147 of these CNVs were de novo, but only 33 (22%) of the de novo CNVs were found on more than one platform. Performing genotype-phenotype correlations, we identified 7 pathogenic and 4 possibly pathogenic CNVs for MR. All 11 of these CNVs were detected by both the Agilent and NimbleGen arrays, 9 by the Affymetrix 500K and Illumina beadchips, and 5 by the SMRT BAC array. Two of the 4 pathogenic or possibly pathogenic CNVs present in the trios tested with the Affymetrix 6.0 array were identified. Our findings demonstrate that different results are obtained with different AGH platforms and illustrate the trade-off that exists between sensitivity and specificity. The large number of apparently false positive CNV calls supports the need for validating clinically important findings with a different methodology. 15 trios were analysed consisting of child (proband) and both normal parents. We performed separate hybridizations for the mother, father, and child and then performed pair-wise comparisons of the normalized hybridization intensities for the child to the mother and of the child to the father in silico.
Project description:Down syndrome (DS) is caused by triplication of Human chromosome 21 (Hsa21) and associated with an array of deleterious phenotypes, including mental retardation, heart defects and immunodeficiency. Genome-wide expression patterns of uncultured peripheral blood cells are useful to understanding of DS-associated immune dysfunction. We used a Human Exon microarray to characterize gene expression in uncultured peripheral blood cells derived from DS individuals and age-matched controls from two age groups: neonate (N) and child (C). A total of 174 transcript clusters (gene-level) with eight located on Hsa21 in N group and 383 transcript clusters including 56 on Hsa21 in C group were significantly dysregulated in DS individuals. Microarray data were validated by quantitative polymerase chain reaction. Functional analysis revealed that the dysregulated genes in DS were significantly enriched in two and six KEGG pathways in N and C group, respectively. These pathways included leukocyte trans-endothelial migration, B cell receptor signaling pathway and primary immunodeficiency, etc., which causally implicated dysfunctional immunity in DS. Our results provided a comprehensive picture of gene expression patterns in DS at the two developmental stages and pointed towards candidate genes and molecular pathways potentially associated with the immune dysfunction in DS.
Project description:In order to study parent-of-origin effects on gene expression, we performed RNAseq analysis (100bp single end reads) of 165 children who formed part of mother/father/child trios where genotype data was available from the HapMap and/or 1000 Genomes Projects. Based on phased genotypes at heterozygous SNP positions, we generated allelic counts for expression of the maternal and paternal alleles in each individual. This analysis reveals significant bias in the expression of the parental alleles for dozens of genes, including both previously known and novel imprinted transcripts.
Project description:Down syndrome (DS) is caused by triplication of Human chromosome 21 (Hsa21) and associated with an array of deleterious phenotypes, including mental retardation, heart defects and immunodeficiency. Spatio-temporal patterns of genome-wide expression are critical to the understanding of DS. We used a Human Exon microarray to characterize gene expression in peripheral blood cells derived from DS and control individuals from two age groups: neonate (N) and child (C). A total of 174 transcript clusters (gene-level) with eight located on Hsa21 in N group and 383 transcript clusters including 57 on Hsa21 in C group were significantly dysregulated in DS individuals. Except for 22 commonly dysregulated genes in the two groups, the remaining dysregulated genes were different between N and C groups, reflecting temporally dynamic variation in gene expression in DS. Dramatically fewer dysregulated Hsa21 genes in N group than those in C group suggested that triplication of Hsa21 per se induces a moderate deregulation at early developmental stages. Further functional analysis revealed that the dysregulated genes in DS were significantly enriched in two KEGG pathways in N group and six pathways in C group. These pathways included leukocyte trans-endothelial migration, B cell receptor signaling pathway and primary immunodeficiency, etc., which causally implicated dysfunctional immunity in DS. Our results provided a comprehensive picture of expression patterns of DS at the two developmental stages and point towards candidate genes and molecular pathways potentially associated with the immune dysfunction in DS. All 37 samples, including 15 DS patients and 22 control individuals were analysized and divided into two age-matched groups: N group (5 DS versus 7 control individuals, age: 3 days to 38 days) and C group (10 DS versus 15 control individuals, age: 1 year to 13 years). N group includes DS (D11-D15) and Control (C16-C22), and C group includes DS (D1-D10) and Control (C1-C15).
Project description:All arrays used in Hyperinfectivity study Merrell DS, Butler SM, Qadri F, Dolganov NA, Alam A, Cohen MB, Calderwood SB, Schoolnik GK, Camilli A. Related Articles Host-induced epidemic spread of the cholera bacterium. Nature. 2002 Jun 6;417(6889):642-5. PMID: 12050664 A=patient A, B=patient B, C=patient C, stationary phase=stationary phase vibrio for comparison, and numbers represent technical replicates of the denoted sample.