Comparative Genomics Unit

Bethesda, MD, United States

Comparative Genomics Unit

Bethesda, MD, United States
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Pierson T.M.,U.S. National Institutes of Health | Adams D.A.,U.S. National Institutes of Health | Markello T.,U.S. National Institutes of Health | Golas G.,U.S. National Institutes of Health | And 13 more authors.
Neurology | Year: 2012

Objective: To utilize high-throughput sequencing to determine the etiology of juvenile-onset neurodegeneration in a 19-year-old woman with progressive motor and cognitive decline. Methods: Exome sequencing identified an initial list of 133,555 variants in the proband's family, which were filtered using segregation analysis, presence in dbSNP, and an empirically derived gene exclusion list. The filtered list comprised 52 genes: 21 homozygous variants and 31 compound heterozygous variants. These variants were subsequently scrutinized with predicted pathogenicita programs and for association with appropriate clinical syndromes. Results: Exome sequencing data identified 2 GLB1 variants (c.602G>A, p.R201H; c.785G>T, p.G262V). β-Galactosidase enzyme analysis prior to our evaluation was reported as normal; however, subsequent testing was consistent with juvenile-onset GM 1-gangliosidosis. Urine oligosaccharide analysis was positive for multiple oligosaccharides with terminal galactose residues. Conclusions: We describe a patient with juvenile-onset neurodegeneration that had eluded diagnosis for over a decade. GM 1-gangliosidosis had previously been excluded from consideration, but was subsequently identified as the correct diagnosis using exome sequencing. Exome sequencing can evaluate genes not previously associated with neurodegeneration, as well as most known neurodegeneration-associated genes. Our results demonstrate the utilita of "agnostic" exome sequencing to evaluate patients with undiagnosed disorders, without prejudice from prior testing results. Copyright © 2012 by AAN Enterprises, Inc.

Arbiza L.,University of Vigo | Patricio M.,University of Vigo | Dopazo H.,Comparative Genomics Unit | Posada D.,University of Vigo
Genome Biology and Evolution | Year: 2011

At a genomic scale, the patterns that have shaped molecular evolution are believed to be largely heterogeneous. Consequently, comparative analyses should use appropriate probabilistic substitution models that capture the main features under which different genomic regions have evolved. While efforts have concentrated in the development and understanding of model selection techniques, no descriptions of overall relative substitution model fit at the genome level have been reported. Here, we provide a characterization of best-fit substitution models across three genomic data sets including coding regions from mammals, vertebrates, and Drosophila (24,000 alignments). According to the Akaike Information Criterion (AIC), 82 of 88 models considered were selected as best-fit models at least in one occasion, although with very different frequencies. Most parameter estimates also varied broadly among genes. Patterns found for vertebrates and Drosophila were quite similar and often more complex than those found in mammals. Phylogenetic trees derived from models in the 95% confidence interval set showed much less variance and were significantly closer to the tree estimated under the best-fit model than trees derived from models outside this interval. Although alternative criteria selected simpler models than the AIC, they suggested similar patterns. All together our results show that at a genomic scale, different gene alignments for the same set of taxa are best explained by a large variety of different substitution models and that model choice has implications on different parameter estimates including the inferred phylogenetic trees. After taking into account the differences related to sample size, our results suggest a noticeable diversity in the underlying evolutionary process. All together, we conclude that the use of model selection techniques is important to obtain consistent phylogenetic estimates from real data at a genomic scale. © The Author(s) 2010.

Santarlasci V.,University of Florence | Maggi L.,University of Florence | Mazzoni A.,University of Florence | Capone M.,University of Florence | And 14 more authors.
European Journal of Immunology | Year: 2014

Human Th17 cells have a limited proliferative capacity compared to other T-cell subsets. We have shown that human Th17 cells display impaired IL-2 production due to IL-4-induced gene 1 (IL4I1) upregulation. Here, we show that in human Th17 cells, IL4I1 also maintains high levels of Tob1, a member of the Tob/BTG (B-cell traslocation gene) antiproliferative protein family, which prevents cell-cycle progression mediated by TCR stimulation. Indeed, Th17 cells exhibited higher levels of Tob1 than Th1 cells in both resting and TCR-activated conditions. Accordingly, the expression of positive regulators of the cell cycle (cyclin A, B, C, and E and Cdk2), as well as of Skp2, which promotes Tob1 degradation, was lower in Th17 cells than in Th1 cells. Tob1 expression in human Th17 cells correlated with both RAR (retinoic acid receptor)-related orphan receptor C (RORC) and IL4I1 levels. However, RORC was not directly involved in the regulation of Tob1 expression, whereas IL4I1 silencing in Th17 cells induced a substantial decrease of Tob1 expression. These data suggest that IL4I1 upregulation in human Th17 cells limits their TCR-mediated expansion not only by blocking the molecular pathway involved in the activation of the IL-2 promoter, but also by maintaining high levels of Tob1, which impairs entry into the cell cycle. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pierson T.M.,U.S. National Institutes of Health | Pierson T.M.,Porter Neuroscience Research Center | Simeonov D.R.,U.S. National Institutes of Health | Sincan M.,U.S. National Institutes of Health | And 13 more authors.
European Journal of Human Genetics | Year: 2012

Fatty acid hydroxylase-associated neurodegeneration due to fatty acid 2-hydroxylase deficiency presents with a wide range of phenotypes including spastic paraplegia, leukodystrophy, and/or brain iron deposition. All previously described families with this disorder were consanguineous, with homozygous mutations in the probands. We describe a 10-year-old male, from a non-consanguineous family, with progressive spastic paraplegia, dystonia, ataxia, and cognitive decline associated with a sural axonal neuropathy. The use of high-throughput sequencing techniques combined with SNP array analyses revealed a novel paternally derived missense mutation and an overlapping novel maternally derived ∼28-kb genomic deletion in FA2H. This patient provides further insight into the consistent features of this disorder and expands our understanding of its phenotypic presentation. The presence of a sural nerve axonal neuropathy had not been previously associated with this disorder and so may extend the phenotype. © 2012 Macmillan Publishers Limited All rights reserved.

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