IU Indianapolis ScholarWorks :: Browsing by Subject "Mutation"

Browsing by Subject "Mutation"

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A global view of the genetic basis of Alzheimer disease
(Springer Nature, 2023) Reitz, Christiane; Pericak-Vance, Margaret A.; Foroud, Tatiana; Mayeux, Richard; Medical and Molecular Genetics, School of Medicine
The risk of Alzheimer disease (AD) increases with age, family history and informative genetic variants. Sadly, there is still no cure or means of prevention. As in other complex diseases, uncovering genetic causes of AD could identify underlying pathological mechanisms and lead to potential treatments. Rare, autosomal dominant forms of AD occur in middle age as a result of highly penetrant genetic mutations, but the most common form of AD occurs later in life. Large-scale, genome-wide analyses indicate that 70 or more genes or loci contribute to AD. One of the major factors limiting progress is that most genetic data have been obtained from non-Hispanic white individuals in Europe and North America, preventing the development of personalized approaches to AD in individuals of other ethnicities. Fortunately, emerging genetic data from other regions - including Africa, Asia, India and South America - are now providing information on the disease from a broader range of ethnicities. Here, we summarize the current knowledge on AD genetics in populations across the world. We predominantly focus on replicated genetic discoveries but also include studies in ethnic groups where replication might not be feasible. We attempt to identify gaps that need to be addressed to achieve a complete picture of the genetic and molecular factors that drive AD in individuals across the globe.
A Multicenter Study of Glucocerebrosidase Mutations in Dementia With Lewy Bodies
(American Medical Association, 2013) Nalls, Michael A.; Duran, Raquel; Lopez, Grisel; Kurzawa-Akanbi, Marzena; McKeith, Ian G.; Chinnery, Patrick F.; Morris, Christopher M.; Theuns, Jessie; Crosiers, David; Cras, Patrick; Engelborghs, Sebastiaan; De Deyn, Peter Paul; Van Broeckhoven, Christine; Mann, David M. A.; Snowden, Julie; Pickering-Brown, Stuart; Halliwell, Nicola; Davidson, Yvonne; Gibbons, Linda; Harris, Jenny; Sheerin, Una-Marie; Bras, Jose; Hardy, John; Clark, Lorraine; Marder, Karen; Honig, Lawrence S.; Berg, Daniela; Maetzler, Walter; Brockmann, Kathrin; Gasser, Thomas; Novellino, Fabiana; Quattrone, Aldo; Annesi, Grazia; De Marco, Elvira Valeria; Rogaeva, Ekaterina; Masellis, Mario; Black, Sandra E.; Bilbao, Juan M.; Foroud, Tatiana; Ghetti, Bernardino; Nichols, William C.; Pankratz, Nathan; Halliday, Glenda; Lesage, Suzanne; Klebe, Stephan; Durr, Alexandra; Duyckaerts, Charles; Brice, Alexis; Giasson, Benoit I.; Trojanowski, John Q.; Hurtig, Howard I.; Tayebi, Nahid; Landazabal, Claudia; Knight, Melanie A.; Keller, Margaux; Singleton, Andrew B.; Wolfsberg, Tyra G.; Sidransky, Ellen; Medicine, School of Medicine
Importance: While mutations in glucocerebrosidase (GBA1) are associated with an increased risk for Parkinson disease (PD), it is important to establish whether such mutations are also a common risk factor for other Lewy body disorders. Objective: To establish whether GBA1 mutations are a risk factor for dementia with Lewy bodies (DLB). DESIGN We compared genotype data on patients and controls from 11 centers. Data concerning demographics, age at onset, disease duration, and clinical and pathological features were collected when available. We conducted pooled analyses using logistic regression to investigate GBA1 mutation carrier status as predicting DLB or PD with dementia status, using common control subjects as a reference group. Random-effects meta-analyses were conducted to account for additional heterogeneity. Setting: Eleven centers from sites around the world performing genotyping. Participants: Seven hundred twenty-one cases met diagnostic criteria for DLB and 151 had PD with dementia. We compared these cases with 1962 controls from the same centers matched for age, sex, and ethnicity. Main outcome measures: Frequency of GBA1 mutations in cases and controls. RESULTS We found a significant association between GBA1 mutation carrier status and DLB, with an odds ratio of 8.28 (95% CI, 4.78-14.88). The odds ratio for PD with dementia was 6.48 (95% CI, 2.53-15.37). The mean age at diagnosis of DLB was earlier in GBA1 mutation carriers than in noncarriers (63.5 vs 68.9 years; P < .001), with higher disease severity scores. Conclusions and relevance: Mutations in GBA1 are a significant risk factor for DLB. GBA1 mutations likely play an even larger role in the genetic etiology of DLB than in PD, providing insight into the role of glucocerebrosidase in Lewy body disease.
A Novel MCPH1 Isoform Complements the Defective Chromosome Condensation of Human MCPH1-Deficient Cells
(Public Library of Science, 2012) Gavvovidis, Ioannis; Rost, Isabell; Trimborn, Marc; Kaiser, Frank J.; Purps, Josephine; Wiek, Constanze; Hanenberg, Helmut; Neitzel, Heidemarie; Schindler, Detlev; Pediatrics, School of Medicine
Biallelic mutations in MCPH1 cause primary microcephaly (MCPH) with the cellular phenotype of defective chromosome condensation. MCPH1 encodes a multifunctional protein that notably is involved in brain development, regulation of chromosome condensation, and DNA damage response. In the present studies, we detected that MCPH1 encodes several distinct transcripts, including two major forms: full-length MCPH1 (MCPH1-FL) and a second transcript lacking the six 3' exons (MCPH1Δe9-14). Both variants show comparable tissue-specific expression patterns, demonstrate nuclear localization that is mediated independently via separate NLS motifs, and are more abundant in certain fetal than adult organs. In addition, the expression of either isoform complements the chromosome condensation defect found in genetically MCPH1-deficient or MCPH1 siRNA-depleted cells, demonstrating a redundancy of both MCPH1 isoforms for the regulation of chromosome condensation. Strikingly however, both transcripts are regulated antagonistically during cell-cycle progression and there are functional differences between the isoforms with regard to the DNA damage response; MCPH1-FL localizes to phosphorylated H2AX repair foci following ionizing irradiation, while MCPH1Δe9-14 was evenly distributed in the nucleus. In summary, our results demonstrate here that MCPH1 encodes different isoforms that are differentially regulated at the transcript level and have different functions at the protein level.
A personalized medicine approach to optimize care for a pediatric cystic fibrosis patient with atypical clinical symptoms
(Wiley, 2024) Lee, Jesun; Husami, Ammar; Arora, Kavisha; Zhang, Weiqiang; Kadri, Ferdous; Yarlagadda, Sunitha; Moon, Changsuk; Mun, Kyu Shik; Zhang, Kejian; Huang, Yunjie; Liyanage, Pramodha; Brewington, John; Clancy, John P.; Shaikhkhalil, Ala; Paul, Grace; Naren, Anjaparavanda P.; Pediatrics, School of Medicine
A Radical Transfer Pathway in Spore Photoproduct Lyase
(ACS, 2013) Yang, Linlin; Nelson, Renae S.; Benjdia, Alhosna; Lin, Gengjie; Telser, Joshua; Stoll, Stefan; Schlichting, Ilme; Li, Lei; Chemistry and Chemical Biology, School of Science
Spore photoproduct lyase (SPL) repairs a covalent UV-induced thymine dimer, spore photoproduct (SP), in germinating endospores and is responsible for the strong UV resistance of endospores. SPL is a radical S-adenosyl-l-methionine (SAM) enzyme, which uses a [4Fe-4S](+) cluster to reduce SAM, generating a catalytic 5'-deoxyadenosyl radical (5'-dA(•)). This in turn abstracts a H atom from SP, generating an SP radical that undergoes β scission to form a repaired 5'-thymine and a 3'-thymine allylic radical. Recent biochemical and structural data suggest that a conserved cysteine donates a H atom to the thymine radical, resulting in a putative thiyl radical. Here we present structural and biochemical data that suggest that two conserved tyrosines are also critical in enzyme catalysis. One [Y99(Bs) in Bacillus subtilis SPL] is downstream of the cysteine, suggesting that SPL uses a novel hydrogen atom transfer (HAT) pathway with a pair of cysteine and tyrosine residues to regenerate SAM. The other tyrosine [Y97(Bs)] has a structural role to facilitate SAM binding; it may also contribute to the SAM regeneration process by interacting with the putative (•)Y99(Bs) and/or 5'-dA(•) intermediates to lower the energy barrier for the second H abstraction step. Our results indicate that SPL is the first member of the radical SAM superfamily (comprising more than 44000 members) to bear a catalytically operating HAT chain.
ATP-Binding Cassette Transporter of Clinical Significance: Sideroblastic Anemia
(MDPI, 2024-06-14) Ogunbileje, John O.; Harris, Neil; Wynn, Tung; Kashif, Reema; Stover, Brian; Osa-Andrews, Bremansu; Pathology and Laboratory Medicine, School of Medicine
The ATP-binding cassette (ABC) transporters are a vast group of 48 membrane proteins, some of which are of notable physiological and clinical importance. Some ABC transporters are involved in functions such as the transport of chloride ions, bilirubin, reproductive hormones, cholesterol, and iron. Consequently, genetic or physiological disruption in these functions is manifested in various disease processes like cystic fibrosis, Tangier disease, and sideroblastic anemia. Among other etiologies, primary sideroblastic anemia results from a genetic mutation in the ATP-binding cassette-7 (ABCB7), a member of the ABC transporter family. There are not many articles specifically tackling the disease processes caused by ABC transporters in detail. Some testing methodologies previously reported in the available literature for investigating sideroblastic anemia need updating. Here, we expound on the relevance of ABCB7 as a clinically important ABC transporter and a rare participant in the disease process of Sideroblastic anemia. The other genetic and secondary etiologies of sideroblastic anemia, which do not involve mutations in the ABCB7 protein, are also described. We review the pathophysiology, clinical course, symptoms, diagnosis, and treatment of sideroblastic anemia with a focus on modern technologies for laboratory testing.
Bannayan Ruvalcaba Riley Syndrome
(American College of Gastroenterology, 2014-01) Sagi, Sashidhar V.; Ballard, Darren D.; Marks, Rebecca A.; Dunn, Katie R.; Kahi, Charles J.; Department of Medicine, IU School of Medicine
A 63-year-old male with history of prostate cancer treated with radiation presented for a colonoscopy for small volume hematochezia. The colonoscopy revealed numerous polyps, which were found to be ganglioneuromas on histological examination. He was referred to medical genetics with suspicion for hamartomatous polyposis syndrome and was found to have a mutation in the PTEN gene. Based on this and suggestive clinical findings, he was diagnosed with Bannayan Ruvalcaba Riley syndrome.
Beyond Tryptophan Synthase: Identification of Genes That Contribute to Chlamydia trachomatis Survival during Gamma Interferon-Induced Persistence and Reactivation
(American Society for Microbiology, 2016-09-19) Muramatsu, Matthew K.; Brothwell, Julie A.; Steinman, Barry D.; Putman, Timothy E.; Rockey, Daniel D.; Nelson, David E.; Department of Microbiology & Immunology, IU School of Medicine
Chlamydia trachomatis can enter a viable but nonculturable state in vitro termed persistence. A common feature of C. trachomatis persistence models is that reticulate bodies fail to divide and make few infectious progeny until the persistence-inducing stressor is removed. One model of persistence that has relevance to human disease involves tryptophan limitation mediated by the host enzyme indoleamine 2,3-dioxygenase, which converts l-tryptophan to N-formylkynurenine. Genital C. trachomatis strains can counter tryptophan limitation because they encode a tryptophan-synthesizing enzyme. Tryptophan synthase is the only enzyme that has been confirmed to play a role in interferon gamma (IFN-γ)-induced persistence, although profound changes in chlamydial physiology and gene expression occur in the presence of persistence-inducing stressors. Thus, we screened a population of mutagenized C. trachomatis strains for mutants that failed to reactivate from IFN-γ-induced persistence. Six mutants were identified, and the mutations linked to the persistence phenotype in three of these were successfully mapped. One mutant had a missense mutation in tryptophan synthase; however, this mutant behaved differently from previously described synthase null mutants. Two hypothetical genes of unknown function, ctl0225 and ctl0694, were also identified and may be involved in amino acid transport and DNA damage repair, respectively. Our results indicate that C. trachomatis utilizes functionally diverse genes to mediate survival during and reactivation from persistence in HeLa cells.
Biphasic Hyalinizing Psammomatous Renal Cell Carcinoma (BHP RCC): A Distinctive Neoplasm Associated with Somatic NF2 Mutations
(Wolters Kluwer, 2020-07) Argani, Pedram; Reuter, Victor E.; Eble, John N.; Vlatkovic, Ljiljana; Yaskiv, Oksana; Swanson, David; Dickson, Brendan C.; Antonescu, Cristina R.; Matoso, Andres; Gagan, Jeffrey; Palsgrove, Doreen N.; Pathology and Laboratory Medicine, School of Medicine
We report 8 cases of a distinctive, previously undescribed renal cell carcinoma associated with somatic mutations in the neurofibromin 2 (NF2) gene. All patients were adults, ranging from 51 to 78 years of age and of cases of known sex 6 of 7 were males. The carcinomas were predominantly unencapsulated, and all had a rounded, nodular interface with the native kidney. The neoplasms were all solid with papillary architecture evident in most cases (7/8), while 1 was only tubular. All cases were biphasic, characterized by larger and smaller carcinoma cells. The smaller cells clustered around basement membrane material similar to the characteristic pattern of the t(6;11) renal cell carcinoma associated with TFEB gene fusions. In 6 of 8 carcinomas, branching nodules of small cells clustered around basement membrane material within larger acini yielding a distinctive glomeruloid pattern. In 6 of 8 carcinomas, the small cells were focally spindle-shaped and unassociated with the basement membrane material. The stroma was sclerotic in all 8 carcinomas, and all 8 contained psammoma bodies that were abundant in 2. In some carcinomas, focal or predominant areas had a less distinctive appearance; 2 had areas that resembled clear cell renal cell carcinoma, 2 had high-grade eosinophilic areas, while 1 had branching tubular architecture that resembled mucinous tubular and spindle cell carcinoma. Two carcinomas demonstrated cellular necrosis. Although we have minimal clinical follow-up, 1 case presented with distant metastasis, progressed and resulted in patient death. While NF2 mutations may be found in other established renal cell carcinoma subtypes (often as secondary genetic alterations), they are potentially the genetic driver of this distinctive entity.
Brain volumetric deficits in MAPT mutation carriers: a multisite study
(Wiley, 2021) Chu, Stephanie A.; Flagan, Taru M.; Staffaroni, Adam M.; Jiskoot, Lize C.; Deng, Jersey; Spina, Salvatore; Zhang, Liwen; Sturm, Virginia E.; Yokoyama, Jennifer S.; Seeley, William W.; Papma, Janne M.; Geschwind, Dan H.; Rosen, Howard J.; Boeve, Bradley F.; Boxer, Adam L.; Heuer, Hilary W.; Forsberg, Leah K.; Brushaber, Danielle E.; Grossman, Murray; Coppola, Giovanni; Dickerson, Bradford C.; Bordelon, Yvette M.; Faber, Kelley; Feldman, Howard H.; Fields, Julie A.; Fong, Jamie C.; Foroud, Tatiana; Gavrilova, Ralitza H.; Ghoshal, Nupur; Graff-Radford, Neill R.; Hsiung, Ging-Yuek Robin; Huey, Edward D.; Irwin, David J.; Kantarci, Kejal; Kaufer, Daniel I.; Karydas, Anna M.; Knopman, David S.; Kornak, John; Kramer, Joel H.; Kukull, Walter A.; Lapid, Maria I.; Litvan, Irene; Mackenzie, Ian R. A.; Mendez, Mario F.; Miller, Bruce L.; Onyike, Chiadi U.; Pantelyat, Alexander Y.; Rademakers, Rosa; Ramos, Eliana Marisa; Roberson, Erik D.; Tartaglia, Maria Carmela; Tatton, Nadine A.; Toga, Arthur W.; Vetor, Ashley; Weintraub, Sandra; Wong, Bonnie; Wszolek, Zbigniew K.; ARTFL/LEFFTDS Consortium; Van Swieten, John C.; Lee, Suzee E.; Medical and Molecular Genetics, School of Medicine
Objective: MAPT mutations typically cause behavioral variant frontotemporal dementia with or without parkinsonism. Previous studies have shown that symptomatic MAPT mutation carriers have frontotemporal atrophy, yet studies have shown mixed results as to whether presymptomatic carriers have low gray matter volumes. To elucidate whether presymptomatic carriers have lower structural brain volumes within regions atrophied during the symptomatic phase, we studied a large cohort of MAPT mutation carriers using a voxelwise approach. Methods: We studied 22 symptomatic carriers (age 54.7 ± 9.1, 13 female) and 43 presymptomatic carriers (age 39.2 ± 10.4, 21 female). Symptomatic carriers' clinical syndromes included: behavioral variant frontotemporal dementia (18), an amnestic dementia syndrome (2), Parkinson's disease (1), and mild cognitive impairment (1). We performed voxel-based morphometry on T1 images and assessed brain volumetrics by clinical subgroup, age, and mutation subtype. Results: Symptomatic carriers showed gray matter atrophy in bilateral frontotemporal cortex, insula, and striatum, and white matter atrophy in bilateral corpus callosum and uncinate fasciculus. Approximately 20% of presymptomatic carriers had low gray matter volumes in bilateral hippocampus, amygdala, and lateral temporal cortex. Within these regions, low gray matter volumes emerged in a subset of presymptomatic carriers as early as their thirties. Low white matter volumes arose infrequently among presymptomatic carriers. Interpretation: A subset of presymptomatic MAPT mutation carriers showed low volumes in mesial temporal lobe, the region ubiquitously atrophied in all symptomatic carriers. With each decade of age, an increasing percentage of presymptomatic carriers showed low mesial temporal volume, suggestive of early neurodegeneration.

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