Project description:<p>Germline mutations are the source of evolution and contribute substantially to many health-related processes. In this study, we use whole genome deep sequencing data from parents-offspring trios to examine the de novo point mutations (DNMs) in the offspring.</p> <p>We studied correlation between parental ages with de novo mutation rates. This study is published in Wong WS, Solomon BD, Bodian DL, Kothiyal P, Eley G, Huddleston KC, Baker R, Thach DC, Iyer RK, Vockley JG, Niederhuber JE. New observations on maternal age effect on germline de novo mutations. Nat Commun. 2016 Jan 19;7:10486 (PMID: <a href="http://www.ncbi.nlm.nih.gov/pubmed/26781218" target="_blank">26781218</a>. Also, we studied differences in molecular signatures in paternal versus maternal origin of de novo mutations. This study is published in Jakob M. Goldmann, Wendy S.W. Wong, Michele Pinelli, Terry Farrah, Dale Bodian, Anna B. Stittrich, Gustavo Glusman, Lisenka E.L.M. Vissers, Alexander Hoischen, Jared C. Roach, Joseph G. Vockley, Joris A. Veltman, Benjamin D. Solomon, Christian Gilissen, John E. Niederhuber. Parent-of-origin specific signatures of de novo mutations. Nat Genet. 2016 Aug;48(8):935-9, PMID: <a href="https://www.ncbi.nlm.nih.gov/pubmed/27322544" target="_blank">27322544</a>.</p>
Project description:This study reports two unrelated patients with a combined immunodeficiency. Whole-exome sequencing of both patients, their healthy parents and siblings identified a single de novo missense variant in ITPR3 (NM_002224.3:c.7570C>T, p.Arg2524Cys) in both index cases. While the mRNA level in patients remained the same as in healthy siblings and controls, the level of protein expression was diminished. It was also shown that the ITPR3 heterozygous p.Arg2524Cys mutation impairs calcium flux function in dermal fibroblast of one patient and in a knock-in Jurkat T cell line. Two additional patients with related phenotypes and the same mutation were further identified and described in the study. The present dataset corresponds to the RNAseq performed on PBMC of patient 2 of the study and healthy controls.
Project description:SNP array was combined with next generation sequencing (NGS) to identify a unique de novo germline mutation in CTCF that became homozygous in the tumor. SNP array shows an LOH through chr16q where CTCF is located.
Project description:Phosphatase and tensin homolog (PTEN) is a tumour suppressor gene associated with inherited tumour susceptibility conditions, macrocephaly, autism, ataxia, tremor and epilepsy. Functional implications of this protein have been investigated in Parkinson’s and Alzheimer’s diseases. We describe the first patient presented with multifocal demyelinating motor neuropathy in association with a de novo PTEN mutation. The pathogenicity of the mutation was supported by altered expression of several proteins involved in tumorigenesis and fibroblasts showed a reversible defect in catalytic activity of PTEN against the secondary substrate, phosphatidylinositol 3,4,-trisphosphate, suggesting a novel and potentially treatable mechanism for multi-focal demyelinating motor neuropathy.
Project description:Dependent on concise, pre-defined protein sequence databases, traditional search algorithms perform poorly when analyzing mass spectra derived from wholly uncharacterized protein products. Conversely, de novo peptide sequencing algorithms can interpret mass spectra without relying on reference databases. However, such algorithms have been difficult to apply to complex protein mixtures, in part due to a lack of methods for automatically validating de novo sequencing results. Here, we present novel metrics for benchmarking de novo sequencing algorithm performance on large scale proteomics datasets, and present a method for accurately calibrating false discovery rates on de novo results. We also present a novel algorithm (LADS) which leverages experimentally disambiguated fragmentation spectra to boost sequencing accuracy and sensitivity. LADS improves sequencing accuracy on longer peptides relative to other algorithms and improves discriminability of correct and incorrect sequences. Using these advancements, we demonstrate accurate de novo identification of peptide sequences not identifiable using database search-based approaches.
Project description:An increasing number of genes involved in chromatin structure and epigenetic regulation has been implicated in a variety of developmental disorders, often including intellectual disability. By trio exome sequencing and subsequent mutational screening we now identified two de novo frameshift mutations and one de novo missense mutation in the CTCF gene in individuals with intellectual disability, microcephaly and growth retardation. Furthermore, a patient with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates and is involved in various chromatin regulation processes such as higher order of chromatin organization, enhancer function, and maintenance of three-dimensional chromatin structure. Transcriptome analyses in all three patients with point mutations revealed deregulation of genes involved in signal transduction and emphasized the role of CTCF in enhancer-driven expression of genes. Our findings indicate that haploinsufficiency of CTCF affects genomic interaction of enhancers and their regulated gene promoters that drive developmental processes and cognition. Comparison of lymphocyte gene expression between 3 de novo CTCF mutation patients and 8 controls (4 technical replicates each, no biological replicates).
Project description:Cystic fibrosis (CF) mouse models exhibit exocrine pancreatic function yet do not develop adipose stores to the levels of non-CF mice. CF mice homozygous for the Cftr mutation (F508del) at 3 weeks (post-weaning) and 6 weeks (young adult) of age had markedly less adipose tissue than non-CF mice. Both 3- and 6-week old mice had dietary lipid absorption and fecal lipid excretion comparable to non-CF controls. Fractional hepatic de novo synthesis of palmitate and stearate (de novo lipogenesis, DNL) as determined by deuterium incorporation was reduced in CF mice. At 3 weeks of age, F508del mice had significantly decreased DNL of palmitate and stearate, by 83% and 80%, respectively. By 6 weeks of age, DNL rates in non-CF mice remained unchanged as compared to 3-week old mice, while DNL rates of F508del mice were still reduced, by 33% and 40%, respectively. Adipose tissue fatty acid profiles were comparable in CF and non-CF mice, indicating that adipose differences are quantitative, not qualitative. A correspondingly lower content of deuterium-labeled fatty acids was found in CF adipose tissue, consistent with reduced deposition of newly made hepatic triglycerides and/or decreased adipose tissue lipogenesis. Hepatic transcriptome analysis revealed lower mRNA expression from several genes involved in fatty acid biosynthesis, suggesting down-regulation of several enzymes in fatty acids synthesis as a mechanism for the reduced lipogenesis. These novel data provide a model for altered fat and fatty acid metabolism in CF, independent of malabsorption, and may partly explain the inability of pancreatic enzyme replacement therapy to completely restore normal body mass to CF patients ∆F508 CF mice and its WT littermates (3-weeks old females, C57BL/6J) were examined. RNA extracted from snapped-frozen livers, 4 replicates per genotype.