Showing papers by "Mingbang Wang published in 2016"

Genome-wide characteristics of de novo mutations in autism

Abstract: De novo mutations (DNMs) are important in Autism Spectrum Disorder (ASD), but so far analyses have mainly been on the ~1.5% of the genome encoding genes. Here, we performed whole genome sequencing (WGS) of 200 ASD parent-child trios and characterized germline and somatic DNMs. We confirmed that the majority of germline DNMs (75.6%) originated from the father, and these increased significantly with paternal age only (p=4.2×10-10). However, when clustered DNMs (those within 20kb) were found in ASD, not only did they mostly originate from the mother (p=7.7×10-13), but they could also be found adjacent to de novo copy number variations (CNVs) where the mutation rate was significantly elevated (p=2.4×10-24). By comparing DNMs detected in controls, we found a significant enrichment of predicted damaging DNMs in ASD cases (p=8.0×10-9; OR=1.84), of which 15.6% (p=4.3×10-3) and 22.5% (p=7.0×10-5) were in the non-coding or genic non-coding, respectively. The non-coding elements most enriched for DNM were untranslated regions of genes, boundaries involved in exon-skipping and DNase I hypersensitive regions. Using microarrays and a novel outlier detection test, we also found aberrant methylation profiles in 2/185 (1.1%) of ASD cases. These same individuals carried independently identified DNMs in the ASD risk- and epigenetic- genes DNMT3A and ADNP. Our data begins to characterize different genome-wide DNMs, and highlight the contribution of non-coding variants, to the etiology of ASD.

Novel loci and pathways significantly associated with longevity

Abstract: Only two genome-wide significant loci associated with longevity have been identified so far, probably because of insufficient sample sizes of centenarians, whose genomes may harbor genetic variants associated with health and longevity. Here we report a genome-wide association study (GWAS) of Han Chinese with a sample size 2.7 times the largest previously published GWAS on centenarians. We identified 11 independent loci associated with longevity replicated in Southern-Northern regions of China, including two novel loci (rs2069837-IL6; rs2440012-ANKRD20A9P) with genome-wide significance and the rest with suggestive significance (P < 3.65 × 10−5). Eight independent SNPs overlapped across Han Chinese, European and U.S. populations, and APOE and 5q33.3 were replicated as longevity loci. Integrated analysis indicates four pathways (starch, sucrose and xenobiotic metabolism; immune response and inflammation; MAPK; calcium signaling) highly associated with longevity (P ≤ 0.006) in Han Chinese. The association with longevity of three of these four pathways (MAPK; immunity; calcium signaling) is supported by findings in other human cohorts. Our novel finding on the association of starch, sucrose and xenobiotic metabolism pathway with longevity is consistent with the previous results from Drosophilia. This study suggests protective mechanisms including immunity and nutrient metabolism and their interactions with environmental stress play key roles in human longevity.

Analysis of the Repertoire Features of TCR Beta Chain CDR3 in Human by High-Throughput Sequencing.

Abstract: Background/Aims: To ward off a wide variety of pathogens, the human adaptive immune system harbors a vast array of T-cell receptors, collectively referred to as the TCR repertoire. Assessment of the repertoire features of TCR is vital for us to deeper understand of immune behaviour and immune response. Methods: In this study, we used a combination of multiplex-PCR, Illumina sequencing and IMGT (ImMunoGeneTics)/HighV-QUEST for a standardized analysis of the repertoire features of TCR beta chain in the blood of healthy individuals, including the repertoire features of public TCR complementarity-determining regions (CDR3) sequences, highly expanded clones, long TCR CDR3 sequences. Results: We found that public CDR3 sequences and high-frequency sequences had the same characteristics, both of them had fewer nucleotide additions and shorter CDR3 length, which were closer to the germline sequence. Moreover, our studies provided evidence that public amino acid sequences are produced by multiple nucleotide sequences. Notably, there was skewed VDJ segment usage in long CDR3 sequences, the expression levels of 10 TRβV segments, 7 TRβJ segments and 2 TRβD segments were significantly different in the long CDR3 sequences compared to the short CDR3 sequences. Moreover, we identified that extensive N additions and increase of D gene usage contributing to TCR CDR3 length, and observed there was distinct usage frequency of amino acids in long CDR3 sequences compared to the short CDR3 sequences. Conclusions: Some repertoire features could be observed in the public sequences, highly abundance clones, and long TCR CDR3 sequences, which might be helpful for further study of immune behavior and immune response.

Diversity of Gut Microbiota Metabolic Pathways in 10 Pairs of Chinese Infant Twins.

Abstract: Early colonization of gut microbiota in human gut is a complex process. It remains unclear when gut microbiota colonization occurs and how it proceeds. In order to study gut microbiota composition in human early life, the present study recruited 10 healthy pairs of twins, including five monozygotic (MZ) and five dizygotic (DZ) twin pairs, whose age ranged from 0 to 6 years old. 20 fecal samples from these twins were processed by shotgun metagenomic sequencing, and their averaged data outputs were generated as 2G per sample. We used MEGAN5 to perform taxonomic and functional annotation of the metagenomic data, and systematically analyzed those 20 samples, including Jaccard index similarity, principle component, clustering, and correlation analyses. Our findings indicated that within our study group: 1) MZ-twins share more microbes than DZ twins or non-twin pairs, 2) gut microbiota distribution is relatively stable at metabolic pathways level, 3) age represents the strongest factor that can account for variation in gut microbiota, and 4) a clear metabolic pathway shift can be observed, which speculatively occurs around the age of 1 year old. This research will serve as a base for future studies of gut microbiota-related disease research.

Multiple gene mutations identified in patients infected with influenza A (H7N9) virus

Abstract: Influenza A (H7N9) virus induced high mortality since 2013. It is important to elucidate the potential genetic variations that contribute to virus infection susceptibilities. In order to identify genetic mutations that might increase host susceptibility to infection, we performed exon sequencing and validated the SNPS by Sanger sequencing on 18 H7N9 patients. Blood samples were collected from 18 confirmed H7N9 patients. The genomic DNA was captured with the Agilent SureSelect Human All Exon kit, sequenced on the Illumina Hiseq 2000, and the resulting data processed and annotated with Genome analysis Tool. SNPs were verified by independent Sanger sequencing. The DAVID database and the DAPPLE database were used to do bioinformatics analysis. Through exon sequencing and Sanger sequencing, we identified 21 genes that were highly associated with H7N9 influenza infection. Protein-protein interaction analysis showed that direct interactions among genetic products were significantly higher than expected (p = 0.004), and DAVID analysis confirmed the defense-related functions of these genes. Gene mutation profiles of survived and non-survived patients were similar, suggesting some of genes identified in this study may be associated with H7N9 influenza susceptibility. Host specific genetic determinants of disease severity identified by this approach may provide new targets for the treatment of H7N9 influenza.

Whole Exome Sequencing Revealed Clinical Relevant Variants in A Family Affected with Autism Spectrum Disorder

Abstract: Chromosomal microarray (CMA) has been suggested for first tier clinical diagnostic test for ASD, with hundreds of genes being associated with ASD by High-throughput Sequencing (HTS). Whole Exome Sequencing (WES) was used to combine with CMA to identify clinical relevant variants in ASD. In our previous work, we used trio (father, mother and proband) based WGS (Whole Genome Sequencing) to reveal clinical relevant de novo or inherited rare variants in half (16/32) of ASD families which all probands have normal or VOUS (Variant of Uncertain Clinical Significance) CMA results. In this study, after screening the chromosome structural abnormalities of a proband affected with ASD by CMA, WES was performed on the patient and the parents, and some rare de novo or inherited rare variants have been detected using trios based bioinformatics analysis. To evaluate the variants in ASD, we rank the variants by SFARI Gene score, HPO (Human Phenotype Ontology) and protein function damaging, manual searching PubMed, and we also validated some of candidate variants in other members in this family by Sanger sequencing. We confirmed a de novo homozygous mutation in SPG11 (p.C209F), two inherited compound heterozygote mutations in SCN9A (p.Q10R and p.R1893H) and BEST1 (p.A135V and p.A297V). We also confirmed heterozygous mutations in TSC1 (p.S487C) and SHANK2 (p.Arg569His) inherited from mother