Browsing by Subject "Human genetics"

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Open Access
Characterization of inherited IRAK-4 deficiency in a patient with acute HHV-6 encephalitis
(2023-07) Demir, Zeynep Güneş Tepe
Human herpesvirus-6 (HHV-6), a ubiquitous virus among humans, typically causes acute febrile illness in children, whereas the majority remain asymptomatic. HHV-6 infection can rarely cause encephalitis, with unknown pathogenesis. We hypothesized that inborn single-gene defects may underlie susceptibility to HHV-6 encephalitis in otherwise healthy children. We performed whole-exome sequencing on genomic DNA of a male child diagnosed with acute HHV-6 encephalitis and found a novel homozygous missense variation (NM_016123.4:c.G236A:p.C79Y) in Interleukin-1 receptor-associated kinase 4 (IRAK4), which is involved in the Toll-Interleukin-1 receptor signaling pathway. Sanger sequencing confirmed that both parents and the sibling were heterozygotes. The p.C79Y that affected an evolutionary conserved residue was predicted to be damaging by in silico algorithms. We found that IRAK-4 expression was severely reduced in patient’s leukocytes. There were similar levels of wild-type (WT) and mutant IRAK-4 when transiently over-expressed in HEK293 cells, however mutant IRAK-4 expression was dramatically decreased upon cycloheximide treatment, compared to the WT. This indicated that the p.C79Y might impair IRAK-4 stability. We found that patient’s leukocytes had diminished innate immune responses to various stimuli inducing different Toll-like receptors and cytosolic nucleic acid sensors, compared to the healthy controls. We also generated IRAK4 knockout HEK293 cells by CRISPR-Cas9 genome editing. Transient expression of mutant IRAK-4 had significantly reduced NFκB-dependent luciferase activity, compared to the WT in IRAK4 knockout cells treated with IL-18. Collectively, the p.C79Y impaired both the expression and function of IRAK-4, leading to diminished immune responses against bacterial and viral stimuli in patient’s leukocytes. Overall, this was the first study demonstrating that inborn errors of immunity could underlie isolated acute HHV-6 encephalitis. Our findings also widened the known genotypic and phenotypic spectrum of inherited IRAK-4 deficiency in humans.
Open Access
Genetic investigation of idiopathic liver injury in children by whole exome sequencing
(2024-07) Lülecioğlu, Aysima Atılgan
Childhood liver diseases, caused by multiple etiologies, pose a significant burden globally. Liver injury of unknown causes remains a challenge in pediatric hepatology. For instance, the etiology remains unexplained in nearly half of the pediatric cases with acute liver failure. This ambiguity impedes early diagnosis and the timely consideration of treatment options. Recent studies, utilized by genome-wide approaches such as whole-exome sequencing (WES), reveal that idiopathic liver injury can be due to hitherto silent monogenic liver diseases. In our study, we aimed to investigate the monogenic determinants of idiopathic liver injury in children. We performed WES on 20 pediatric patients presenting with either recurrent elevated liver transaminases (rELT) of unknown etiology or indeterminate acute liver failure (ALF). We searched for potential disease-causing variants in a manually curated panel of 380 genes associated with inherited monogenic diseases with hepatobiliary phenotypes. We identified rare nonsynonymous variants in nine genes in total 6 patients, five rELT patients and one ALF patient. Then, we evaluated the causal concordance between the gene mutated and the clinical phenotype observed in each patient through an in-depth case-level assessment. Overall, we established a genetic diagnosis in four out of 10 rELT patients. We identified two novel mutations in ACOX2 and PYGL, expanding the spectrum of genetic mutations implicated in monogenic liver diseases. Additionally, we discovered two previously-reported morbid mutations in ABCB4 and PHKA2. Moreover, we identified five variants of uncertain significance (VUS) in CDAN1, JAG1, PCK2, SLC27A5, or VPS33B in rELT or ALF patients. This study further supports the utility of WES in clinical settings to enhance our understanding and management of idiopathic liver diseases in children, providing early diagnosis and precise treatment. By identifying the genetic variants contributing to liver injury, clinicians can predict disease progression more accurately, provide more personalized treatment strategies, and make decisions on liver transplantation when necessary.
Open Access
A global reference for human genetic variation
(Nature Publishing Group, 2015) Auton, A.; Abecasis, G. R.; Altshuler, D. M.; Durbin, R. M.; Bentley, D. R.; Chakravarti, A.; Clark, A. G.; Donnelly, P.; Eichler, E. E.; Flicek, P.; Gabriel, S. B.; Gibbs, R. A.; Green, E. D.; Hurles, M. E.; Knoppers, B. M.; Korbel, J. O.; Lander, E. S.; Lee, C.; Lehrach, H.; Mardis, E. R.; Marth, G. T.; McVean, G. A.; Nickerson, D. A.; Schmidt, J. P.; Sherry, S. T.; Wang, J.; Wilson, R. K.; Boerwinkle, E.; Doddapaneni, H.; Han, Y.; Korchina, V.; Kovar, C.; Lee, S.; Muzny, D.; Reid, J. G.; Zhu, Y.; Chang, Y.; Feng, Q.; Fang, X.; Guo, X.; Jian, M.; Jiang, H.; Jin, X.; Lan, T.; Li, G.; Li, J.; Li, Y.; Liu, S.; Liu, X.; Lu, Y.; Ma, X.; Tang, M.; Wang, B.; Wang, G.; Wu, H.; Wu, R.; Xu, X.; Yin, Y.; Zhang, D.; Zhang, W.; Zhao, J.; Zhao, M.; Zheng, X.; Gupta, N.; Gharani, N.; Toji, L. H.; Gerry, N. P.; Resch, A. M.; Barker, J.; Clarke, L.; Gil, L.; Hunt, S. E.; Kelman, G.; Kulesha, E.; Leinonen, R.; McLaren, W. M.; Radhakrishnan, R.; Roa, A.; Smirnov, D.; Smith, R. E.; Streeter, I.; Thormann, A.; Toneva, I.; Vaughan, B.; Zheng-Bradley, X.; Grocock, R.; Humphray, S.; James, T.; Kingsbury, Z.; Sudbrak, R.; Albrecht, M. W.; Amstislavskiy, V. S.; Borodina, T. A.; Lienhard, M.; Mertes, F.; Sultan, M.; Timmermann, B.; Yaspo, Marie-Laure; Fulton, L.; Ananiev, V.; Belaia, Z.; Beloslyudtsev, D.; Bouk, N.; Chen, C.; Church, D.; Cohen, R.; Cook, C.; Garner, J.; Hefferon, T.; Kimelman, M.; Liu, C.; Lopez, J.; Meric, P.; O'Sullivan, C.; Ostapchuk, Y.; Phan, L.; Ponomarov, S.; Schneider, V.; Shekhtman, E.; Sirotkin, K.; Slotta, D.; Zhang, H.; Balasubramaniam, S.; Burton, J.; Danecek, P.; Keane, T. M.; Kolb-Kokocinski, A.; McCarthy, S.; Stalker, J.; Quail, M.; Davies, C. J.; Gollub, J.; Webster, T.; Wong, B.; Zhan, Y.; Campbell, C. L.; Kong, Y.; Marcketta, A.; Yu, F.; Antunes, L.; Bainbridge, M.; Sabo, A.; Huang, Z.; Coin, L. J. M.; Fang, L.; Li, Q.; Li, Z.; Lin, H.; Liu, B.; Luo, R.; Shao, H.; Xie, Y.; Ye, C.; Yu, C.; Zhang, F.; Zheng, H.; Zhu, H.; Alkan, C.; Dal, E.; Kahveci, F.; Garrison, E. P.; Kural, D.; Lee, W. P.; Leong, W. F.; Stromberg, M.; Ward, A. N.; Wu, J.; Zhang, M.; Daly, M. J.; DePristo, M. A.; Handsaker, R. E.; Banks, E.; Bhatia, G.; Del Angel, G.; Genovese, G.; Li, H.; Kashin, S.; McCarroll, S. A.; Nemesh, J. C.; Poplin, R. E.; Yoon, S. C.; Lihm, J.; Makarov, V.; Gottipati, S.; Keinan, A.; Rodriguez-Flores, J. L.; Rausch, T.; Fritz, M. H.; Stütz, A. M.; Beal, K.; Datta, A.; Herrero, J.; Ritchie, G. R. S.; Zerbino, D.; Sabeti, P. C.; Shlyakhter, I.; Schaffner, S. F.; Vitti, J.; Cooper, D. N.; Ball, E. V.; Stenson, P. D.; Barnes, B.; Bauer, M.; Cheetham, R. K.; Cox, A.; Eberle, M.; Kahn, S.; Murray, L.; Peden, J.; Shaw, R.; Kenny, E. E.; Batzer, M. A.; Konkel, M. K.; Walker, J. A.; MacArthur, D. G.; Lek, M.; Herwig, R.; Ding, L.; Koboldt, D. C.; Larson, D.; Ye, K.; Gravel, S.; Swaroop, A.; Chew, E.; Lappalainen, T.; Erlich, Y.; Gymrek, M.; Willems, T. F.; Simpson, J. T.; Shriver, M. D.; Rosenfeld, J. A.; Bustamante, C. D.; Montgomery, S. B.; De La Vega, F. M.; Byrnes, J. K.; Carroll, A. W.; DeGorter, M. K.; Lacroute, P.; Maples, B. K.; Martin, A. R.; Moreno-Estrada, A.; Shringarpure, S. S.; Zakharia, F.; Halperin, E.; Baran, Y.; Cerveira, E.; Hwang, J.; Malhotra, A.; Plewczynski, D.; Radew, K.; Romanovitch, M.; Zhang, C.; Hyland, F. C. L.; Craig, D. W.; Christoforides, A.; Homer, N.; Izatt, T.; Kurdoglu, A. A.; Sinari, S. A.; Squire, K.; Xiao, C.; Sebat, J.; Antaki, D.; Gujral, M.; Noor, A.; Ye, K.; Burchard, E. G.; Hernandez, R. D.; Gignoux, C. R.; Haussler, D.; Katzman, S. J.; Kent, W. J.; Howie, B.; Ruiz-Linares, A.; Dermitzakis, E. T.; Devine, S. E.; Kang, H. M.; Kidd, J. M.; Blackwell, T.; Caron, S.; Chen, W.; Emery, S.; Fritsche, L.; Fuchsberger, C.; Jun, G.; Li, B.; Lyons, R.; Scheller, C.; Sidore, C.; Song, S.; Sliwerska, E.; Taliun, D.; Tan, A.; Welch, R.; Wing, M. K.; Zhan, X.; Awadalla, P.; Hodgkinson, A.; Li, Y.; Shi, X.; Quitadamo, A.; Lunter, G.; Marchini, J. L.; Myers, S.; Churchhouse, C.; Delaneau, O.; Gupta-Hinch, A.; Kretzschmar, W.; Iqbal, Z.; Mathieson, I.; Menelaou, A.; Rimmer, A.; Xifara, D. K.; Oleksyk, T. K.; Fu, Y.; Liu, X.; Xiong, M.; Jorde, L.; Witherspoon, D.; Xing, J.; Browning, B. L.; Browning, S. R.; Hormozdiari, F.; Sudmant, P. H.; Khurana, E.; Tyler-Smith, C.; Albers, C. A.; Ayub, Q.; Chen, Y.; Colonna, V.; Jostins, L.; Walter, K.; Xue, Y.; Gerstein, M. B.; Abyzov, A.; Balasubramanian, S.; Chen, J.; Clarke, D.; Fu, Y.; Harmanci, A. O.; Jin, M.; Lee, D.; Liu, J.; Mu, X. J.; Zhang, J.; Zhang, Y.; Hartl, C.; Shakir, K.; Degenhardt, J.; Meiers, S.; Raeder, B.; Casale, F. P.; Stegle, O.; Lameijer, E. W.; Hall, I.; Bafna, V.; Michaelson, J.; Gardner, E. J.; Mills, R. E.; Dayama, G.; Chen, K.; Fan, X.; Chong, Z.; Chen, T.; Chaisson, M. J.; Huddleston, J.; Malig, M.; Nelson, B. J.; Parrish, N. F.; Blackburne, B.; Lindsay, S. J.; Ning, Z.; Zhang, Y.; Lam, H.; Sisu, C.; Challis, D.; Evani, U. S.; Lu, J.; Nagaswamy, U.; Yu, J.; Li, W.; Habegger, L.; Yu, H.; Cunningham, F.; Dunham, I.; Lage, K.; Jespersen, J. B.; Horn, H.; Kim, D.; Desalle, R.; Narechania, A.; Sayres, M. A. W.; Mendez, F. L.; Poznik, G. D.; Underhill, P. A.; Mittelman, D.; Banerjee, R.; Cerezo, M.; Fitzgerald, T. W.; Louzada, S.; Massaia, A.; Yang, F.; Kalra, D.; Hale, W.; Dan, X.; Barnes, K. C.; Beiswanger, C.; Cai, H.; Cao, H.; Henn, B.; Jones, D.; Kaye, J. S.; Kent, A.; Kerasidou, A.; Mathias, R.; Ossorio, P. N.; Parker, M.; Rotimi, C. N.; Royal, C. D.; Sandoval, K.; Su, Y.; Tian, Z.; Tishkoff, S.; Via, M.; Wang, Y.; Yang, H.; Yang, L.; Zhu, J.; Bodmer, W.; Bedoya, G.; Cai, Z.; Gao, Y.; Chu, J.; Peltonen, L.; Garcia-Montero, A.; Orfao, A.; Dutil, J.; Martinez-Cruzado, J. C.; Mathias, R. A.; Hennis, A.; Watson, H.; McKenzie, C.; Qadri, F.; LaRocque, R.; Deng, X.; Asogun, D.; Folarin, O.; Happi, C.; Omoniwa, O.; Stremlau, M.; Tariyal, R.; Jallow, M.; Joof, F. S.; Corrah, T.; Rockett, K.; Kwiatkowski, D.; Kooner, J.; Hien, T. T.; Dunstan, S. J.; ThuyHang, N.; Fonnie, R.; Garry, R.; Kanneh, L.; Moses, L.; Schieffelin, J.; Grant, D. S.; Gallo, C.; Poletti, G.; Saleheen, D.; Rasheed, A.; Brooks, L. D.; Felsenfeld, A. L.; McEwen, J. E.; Vaydylevich, Y.; Duncanson, A.; Dunn, M.; Schloss, J. A.
The 1000 Genomes Project set out to provide a comprehensive description of common human genetic variation by applying whole-genome sequencing to a diverse set of individuals from multiple populations. Here we report completion of the project, having reconstructed the genomes of 2,504 individuals from 26 populations using a combination of low-coverage whole-genome sequencing, deep exome sequencing, and dense microarray genotyping. We characterized a broad spectrum of genetic variation, in total over 88 million variants (84.7 million single nucleotide polymorphisms (SNPs), 3.6 million short insertions/deletions (indels), and 60,000 structural variants), all phased onto high-quality haplotypes. This resource includes >99% of SNP variants with a frequency of >1% for a variety of ancestries. We describe the distribution of genetic variation across the global sample, and discuss the implications for common disease studies. © 2015 Macmillan Publishers Limited. All rights reserved.
Open Access
Identification and characterization of exonic variants related with familial essential tremor
(2017-07) Tuncay, İslam Oğuz
Essential tremor (ET) is the most common movement disorder in humans. Despite its high heritability and frequency, the genetic basis and pathophysiology of ET is not well understood. In this study, whole exome sequencing and pedigree analyses were performed in unrelated ET families from Anatolia. Whole exome sequencing analysis of family members resulted in the identification of MMP19 p.R456Q in families ET-5 and ET-49. Expression analysis in mice showed a possible developmental pattern for expression of MMP-19 as well as a tissue-specific expression pattern showing high levels of expression in the brain for this gene. Two other families, ET-17 and ET-19 were also analyzed; however the results were not able to identify variant cosegregating with ET in these families. Identification of the new genes related with ET will provide invaluable insights into the underlying mechanism of thıs most common movement disorder and will potentially open new avenues for its treatment.
Open Access
Identification of candidate genes for familial essential tremor
(2016-09) Şen, Merve
Essential tremor (ET) is one of the most common movement disorders in humans and is characterized by action tremors that occur during voluntary motion. However, due to the strong heterogeneity exhibited by ET patients at etiological, clinical and pathological levels, the genetic architecture and pathophysiology of the disease remain largely unknown. In this thesis, whole exome sequencing and pedigree analysis were performed in 3 ET families with histories consistent with an autosomal dominant pattern of inheritance. In two independent families, we observed a rare variant that cosegregated with the disease and was predicted to affect the function of the protein. In one of these families, a homozygous variant was identified in one affected patient and a heterozygous variant was determined in five affected family members. In a second, four-generation Turkish family, the same heterozygous variant was identified in three ET cases while remaining absent in unaffected family members. In addition, whole exome sequencing allowed us to demonstrate that other missense mutation segregate with essential tremor in a different consanguineous Turkish family. Both variants were observed to involve amino acid substitutions of highly conserved domains. Furthermore, both of the affected genes are expressed in the brain and function as regulatory elements of the central nervous system. Consequently, we propose that these variants are risk factors involved in the etiology of hereditary ET, and suggest that whole exome sequencing can serve as an effective means of identifying other alleles associated with the disease.
Open Access
An integrated map of structural variation in 2,504 human genomes
(Nature Publishing Group, 2015) Sudmant, P. H.; Rausch, T.; Gardner, E. J.; Handsaker, R. E.; Abyzov, A.; Huddleston, J.; Zhang, Y.; Ye, K.; Jun, G.; Fritz, M. Hsi-Yang; Konkel, M. K.; Malhotra, A.; Stütz, A. M.; Shi, X.; Casale, F. P.; Chen, J.; Hormozdiari, F.; Dayama, G.; Chen, K.; Malig, M.; Chaisson, M. J. P.; Walter, K.; Meiers, S.; Kashin, S.; Garrison, E.; Auton, A.; Lam, H. Y. K.; Mu, X. J.; Alkan, C.; Antaki, D.; Bae, T.; Cerveira, E.; Chines, P.; Chong, Z.; Clarke, L.; Dal, E.; Ding, L.; Emery, S.; Fan, X.; Gujral, M.; Kahveci, F.; Kidd, J. M.; Kong, Y.; Lameijer, Eric-Wubbo; McCarthy, S.; Flicek, P.; Gibbs, R. A.; Marth, G.; Mason, C. E.; Menelaou, A.; Muzny, D. M.; Nelson, B. J.; Noor, A.; Parrish, N. F.; Pendleton, M.; Quitadamo, A.; Raeder, B.; Schadt, E. E.; Romanovitch, M.; Schlattl, A.; Sebra, R.; Shabalin, A. A.; Untergasser, A.; Walker J. A.; Wang, M.; Yu, F.; Zhang, C.; Zhang, J.; Zheng-Bradley, X.; Zhou, W.; Zichner, T.; Sebat, J.; Batzer, M. A.; McCarroll, S. A.; Mills, R. E.; Gerstein, M. B.; Bashir, A.; Stegle, O.; Devine, S. E.; Lee, C.; Eichler, E. E.; Korbel, J. O.
Structural variants are implicated in numerous diseases and make up the majority of varying nucleotides among human genomes. Here we describe an integrated set of eight structural variant classes comprising both balanced and unbalanced variants, which we constructed using short-read DNA sequencing data and statistically phased onto haplotype blocks in 26 human populations. Analysing this set, we identify numerous gene-intersecting structural variants exhibiting population stratification and describe naturally occurring homozygous gene knockouts that suggest the dispensability of a variety of human genes. We demonstrate that structural variants are enriched on haplotypes identified by genome-wide association studies and exhibit enrichment for expression quantitative trait loci. Additionally, we uncover appreciable levels of structural variant complexity at different scales, including genic loci subject to clusters of repeated rearrangement and complex structural variants with multiple breakpoints likely to have formed through individual mutational events. Our catalogue will enhance future studies into structural variant demography, functional impact and disease association.