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Fusing Peptide Epitopes for Advanced Multiplex Serological Testing for SARS-CoV-2 Antibody Detection. ACS BIO & MED CHEM AU 2024; 4:37-52. [PMID: 38404747 PMCID: PMC10885102 DOI: 10.1021/acsbiomedchemau.3c00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 02/27/2024]
Abstract
The tragic COVID-19 pandemic, which has seen a total of 655 million cases worldwide and a death toll of over 6.6 million seems finally tailing off. Even so, new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to arise, the severity of which cannot be predicted in advance. This is concerning for the maintenance and stability of public health, since immune evasion and increased transmissibility may arise. Therefore, it is crucial to continue monitoring antibody responses to SARS-CoV-2 in the general population. As a complement to polymerase chain reaction tests, multiplex immunoassays are elegant tools that use individual protein or peptide antigens simultaneously to provide a high level of sensitivity and specificity. To further improve these aspects of SARS-CoV-2 antibody detection, as well as accuracy, we have developed an advanced serological peptide-based multiplex assay using antigen-fused peptide epitopes derived from both the spike and the nucleocapsid proteins. The significance of the epitopes selected for antibody detection has been verified by in silico molecular docking simulations between the peptide epitopes and reported SARS-CoV-2 antibodies. Peptides can be more easily and quickly modified and synthesized than full length proteins and can, therefore, be used in a more cost-effective manner. Three different fusion-epitope peptides (FEPs) were synthesized and tested by enzyme-linked immunosorbent assay (ELISA). A total of 145 blood serum samples were used, compromising 110 COVID-19 serum samples from COVID-19 patients and 35 negative control serum samples taken from COVID-19-free individuals before the outbreak. Interestingly, our data demonstrate that the sensitivity, specificity, and accuracy of the results for the FEP antigens are higher than for single peptide epitopes or mixtures of single peptide epitopes. Our FEP concept can be applied to different multiplex immunoassays testing not only for SARS-CoV-2 but also for various other pathogens. A significantly improved peptide-based serological assay may support the development of commercial point-of-care tests, such as lateral-flow-assays.
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A unique investigation of thallium, tellurium, osmium, and other heavy metals in recurrent pregnancy loss: A novel approach. Int J Gynaecol Obstet 2023; 160:790-796. [PMID: 35929844 DOI: 10.1002/ijgo.14390] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 06/26/2022] [Accepted: 07/28/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To study the impact of heavy metals especially tellurium, thallium, and osmium, in recurrent pregnancy loss (RPL) and to study their association with antioxidant status and DNA damage. METHODS This case-control study included women with RPL (n = 30) and healthy pregnant women as control (n = 30). Following blood collection, serum levels of thallium, tellurium, osmium, lead, mercury, and cadmium were estimated by inductively coupled plasma mass spectrophotometer. RESULTS Women with RPL exhibited significantly higher levels of heavy metals (P < 0.001) when compared with control women. Intriguingly, increased levels of serum thallium, tellurium, osmium, and lead were negatively correlated with total antioxidant status (P < 0.05). Further, the RPL group demonstrated strong positive correlation between heavy metals (thallium, tellurium, osmium, lead) and DNA damage (P < 0.05). No significant correlation between other heavy metals and markers of cellular damage was noted. CONCLUSION Enhanced levels of heavy metals in women with RPL and correlation of thallium, tellurium, osmium, and lead with markers of cellular damage reflect the role of heavy metal poisoning, especially thallium, tellurium, and osmium, as potential risk factor in the etiology underlying recurrent miscarriage.
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Isolated Congenital Anosmia: Case Report and Literature Review. EAR, NOSE & THROAT JOURNAL 2022:1455613221111496. [PMID: 35931064 DOI: 10.1177/01455613221111496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Isolated congenital anosmia (ICA) is a rare entity worldwide with poorly understood genetic variation. The diagnosis of ICA is made by exclusion of acquired causes of anosmia. Additionally, magnetic resonance imaging in ICA is essential for diagnosis, as it shows reduced or absent development of olfactory bulbs and shallow olfactory sulci. Here, we present the case of a 21-year-old man who presented to our clinic with complete anosmia since birth. The patient's history was negative for acquired causes of anosmia, and the physical examinations of the ears, nose, throat, head, and neck were all not remarkable. Smell testing revealed complete anosmia. The CT imaging was unremarkable; however, magnetic resonance imaging of the anterior brain and olfactory region showed bilaterally absent olfactory bulbs and olfactory tracts, with a shallow olfactory groove. The patient was then subjected to whole exome sequencing. Bioinformatics analysis was performed on the 37 genes associated with olfactory dysfunction, in which a missense variant was identified in the HS6ST1(NM_004807.3) gene was identified, which insilico tools predicted to be likely pathogenic. The results of this patient's genetic analysis add to the possible genetic culprits reported in ICA cases. Additional genetic analyses are required to validate mutations and understand the heterogeneity of disease representation.
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Biomarker-Determined Nonylphenol Exposure and Associated Risks in Children of Thailand, Indonesia, and Saudi Arabia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10229-10238. [PMID: 35801963 DOI: 10.1021/acs.est.2c01404] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nonylphenol (NP) is an endocrine disruptor and environmental contaminant. Yet, data on individual body burdens and potential health risks in humans, especially among children, are scarce. We analyzed two specific urinary NP metabolites, hydroxy-NP (OH-NP) and oxo-NP. In contrast to parent NP, OH-NP has a much higher urinary excretion fraction (Fue), and both are insusceptible to external contamination. We investigated spot urine samples from school children of Thailand (n = 104), Indonesia (n = 89), and Saudi Arabia (n = 108) and could quantify OH-NP in 100% of Indonesian and Saudi children (median concentrations: 8.12 and 8.57 μg/L) and in 76% of Thai children (1.07 μg/L). Median oxo-NP concentrations were 0.95, 1.10, and <0.25 μg/L, respectively, in line with its lower Fue. Median daily NP intakes (DIs), back-calculated from urinary OH-NP concentrations, were significantly higher in Indonesia and Saudi Arabia [0.47 and 0.36 μg/(kg bw·d), respectively] than in Thailand [0.06 μg/(kg bw·d)]. Maximum DIs were close to the preliminary tolerable DI of 5 μg/(kg bw·d) from the Danish Environmental Protection Agency. Dominant sources of exposure or relevant exposure pathways could not be readily identified by questionnaire analyses and also potentially varied by region. The novel biomarkers provide long-needed support to the quantitative exposure and risk assessment of NP.
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Urinary Concentrations of Major Phthalate and Alternative Plasticizer Metabolites in Children of Thailand, Indonesia, and Saudi Arabia, and Associated Risks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16526-16537. [PMID: 34846872 DOI: 10.1021/acs.est.1c04716] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Phthalates are widely used in consumer products and are well-known for adverse endocrine outcomes. Di-(2-ethylhexyl) phthalate (DEHP), one of the most extensively used phthalates, has been rapidly substituted with alternative plasticizers in many consumer products. The aim of this study was to assess urinary phthalate and alternative plasticizer exposure and associated risks in children of three Asian countries with different geographical, climate, and cultural characteristics. Children were recruited from elementary schools of Saudi Arabia (n = 109), Thailand (n = 104), and Indonesia (n = 89) in 2017-2018, and their urine samples were collected. Metabolites of major phthalates and alternative plasticizers were measured in the urine samples by HPLC-MS/MS. Urinary metabolite levels differed substantially between the three countries. Metabolite levels of diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP), di(2-ethylhexyl) terephthalate (DEHTP), and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) were the highest in Saudi children: Median urinary concentrations of oxo-MiNP, OH-MiDP, 5cx-MEPTP, and OH-MINCH were 8.3, 8.4, 128.0, and 2.9 ng/mL, respectively. Urinary DEHP metabolite concentrations were the highest in the Indonesian children. The hazard index (HI) derived for the plasticizers with antiandrogenicity based reference doses (RfDAA) was >1 in 86%, 80%, and 49% of the Saudi, Indonesian, and Thai children, respectively. DEHP was identified as a common major risk driver for the children of all three countries, followed by DnBP and DiBP depending on the country. Among alternative plasticizers, urinary DEHTP metabolites were detected at levels comparable to those of DEHP metabolites or higher among the Saudi children, and about 4% of the Saudi children exceeded the health based human biomonitoring (HBM)-I value. Priority plasticizers that were identified among the children of three countries warrant refined exposure assessment for source identification and relevant exposure reduction measures.
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Measurement of the flux-averaged inclusive charged-current electron neutrino and antineutrino cross section on argon using the NuMI beam and the MicroBooNE detector. Int J Clin Exp Med 2021. [DOI: 10.1103/physrevd.104.052002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Assessment of DNA damage in relation to heavy metal induced oxidative stress in females with recurrent pregnancy loss (RPL). Saudi J Biol Sci 2021; 28:5403-5407. [PMID: 34466121 PMCID: PMC8381069 DOI: 10.1016/j.sjbs.2021.05.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/09/2022] Open
Abstract
Pregnancy termination consecutively for three or more times during the first trimester is termed as Recurrent pregnancy loss (RPL). In addition to the abnormal karyotype, heavy metal induced oxidative damage may contribute as prominent etiological factor in pregnancy termination. Oxidative stress is considered crucial in etiology underlying RPL with altered antioxidant status and subsequent DNA damage. The current case controlled study investigated Total antioxidant capacity (TAC), DNA damage (8OHdG) and heavy metals in RPL group (n = 30) and the women with successful pregnancies and no cases of miscarriage as control group (30 women). Heavy metals -Antimony (Sb) and Arsenic (As) were measured by Inductively Coupled Plasma Mass spectrophotometry (ICP-MS). There was significant decrease in levels of TAC in RPL group compared to healthy pregnant women (P < 0.05). On contrary, elevated levels of As and Sb were observed in RPL group with subsequent increase in the levels of 8OHdG (P < 0.001); indicating extensive DNA damage in these patients. Furthermore, increased levels of As and Sb in RPL group were positively correlated with 8OHdG and negatively with total antioxidant capacity. The outcome of the study provides clear insight of the role of metal induced oxidative stress that plays a vital role in the pathophysiology underlying RPL.
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Convolutional neural network for multiple particle identification in the MicroBooNE liquid argon time projection chamber. Int J Clin Exp Med 2021. [DOI: 10.1103/physrevd.103.092003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Landscape of somatic mutations in breast cancer: new opportunities for targeted therapies in Saudi Arabian patients. Oncotarget 2021; 12:686-697. [PMID: 33868589 PMCID: PMC8021026 DOI: 10.18632/oncotarget.27909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/19/2021] [Indexed: 12/24/2022] Open
Abstract
Breast cancer (BCa) ranks first in incidence rate among cancers in Arab females. The association between genetic polymorphisms in tumor suppressor genes and the risk of BCa has been studied in many ethnic populations with conflicting conclusions while Arab females and Saudi Arabian studies are still lacking. We screened a cohort of Saudi BCa patients by NGS using a bespoke gene panel to clarify the genetic landscape of this population, correlating and assessing genetic findings with clinical outcomes. We identified a total of 263 mutations spanning 51 genes, including several frequently mutated. Among the genes analyzed, the highest mutation rates were found in PIK3CA (12.9%), BRCA2 (11.7%), BRCA1 (10.2%), TP53 (6.0%), MSH2 (3.8%), PMS2 (3.8%), BARD1 (3.8%), MLH1 (3.4%), CDH1 (3.0%), RAD50 (3.0%), MSH6 (3.0%), NF1 (2.6%), in addition to others. We identified multiple common recurrent variants and previously reported mutations. We also identified 46 novel variants in 22 genes that were predicted to have a pathogenic effect. Survival analysis according to the four most common mutations (BRCA1, BRCA2, TP53, and PIK3CA) showed reduced survival in BRCA1 and BRCA2-mutant patients compared to total patients. Moreover, BRCA2 was demonstrated as an independent predictor of reduced survival using independent Cox proportional hazard models. We reveal the landscape of the mutations associated with BCa in Saudi women, highlighting the importance of routine genetic sequencing in implementation of precision therapies in KSA.
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Selenium Nanoparticles by Moderating Oxidative Stress Promote Differentiation of Mesenchymal Stem Cells to Osteoblasts. Int J Nanomedicine 2021; 16:331-343. [PMID: 33488075 PMCID: PMC7814244 DOI: 10.2147/ijn.s285233] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022] Open
Abstract
Purpose Redox homeostasis plays an important role in the osteogenic differentiation of human mesenchymal stem cells (hMSCs) for bone engineering. Oxidative stress (OS) is believed to induce osteoporosis by changing bone homeostasis. Selenium nanoparticles (SeNPs), an antioxidant with pleiotropic pharmacological activity, prevent bone loss. However, the molecular mechanism underlying the osteogenic activity during hMSC–SeNP interaction is unclear. Methods This study assessed the effects of different concentrations (25, 50, 100, and 300 ng/mL) of SeNPs on the cell viability and differentiation ability of human embryonic stem cell-derived hMSCs. In addition, we analyzed OS markers and their effect on mitogen-activated protein kinase (MAPK) and Forkhead box O3 (FOXO3) during osteogenesis. Results SeNPs increased the cell viability of hMSCs and induced their differentiation toward an osteogenic over an adipogenic lineage by enhancing osteogenic transcription and mineralization, while inhibiting Nile red staining and adipogenic gene expression. By preventing excessive reactive oxygen species accumulation, SeNPs increased antioxidant levels in hMSCs undergoing osteogenesis compared to untreated cells. In addition, SeNPs significantly upregulated the gene and protein expression of phosphorylated c-Jun N-terminal kinase (JNK) and FOXO3a, with no significant change in the expression levels of extracellular signal-related kinase (ERK) and p38 MAPK. Conclusion The results approved that low concentrations of SeNPs might enhance the cell viability and osteogenic potential of hMSCs by moderating OS. Increased JNK and FOXO3a expression shows that SeNPs might enhance osteogenesis via activation of the JNK/FOXO3 pathway. In addition, SeNP co-supplementation might prevent bone loss by enhancing osteogenesis and, thus, can be an effective candidate for treating osteoporosis through cell-based therapy.
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Epigallocatechin gallate and coenzyme Q10 attenuate cisplatin-induced hepatotoxicity in rats via targeting mitochondrial stress and apoptosis. J Biochem Mol Toxicol 2021; 35:e22701. [PMID: 33393703 DOI: 10.1002/jbt.22701] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/14/2020] [Accepted: 12/12/2020] [Indexed: 12/21/2022]
Abstract
Despite the extensive use of cisplatin (CP) as a chemotherapeutic agent, its clinical use is often restricted by undesirable side effects, such as toxicity to normal tissues. The aim of this study was to probe the effect of a combinatorial treatment of low multiple doses of antioxidants on CP-induced toxicity and the mitochondrial apoptotic pathway in hepatocytes. Animals received a single toxic dose of CP (7.5 mg/kg body weight) with or without combined multiple doses of epigallocatechin gallate (EGCG) and coenzyme Q10 (CoQ10) (15 and 5 mg/kg body weight, respectively). CP-treated animals showed altered biochemical parameters, denoting hepatotoxicity, which was markedly improved by the multidose treatment with EGCG + CoQ10. The increased levels of oxidants found in the cytosolic and mitochondrial fractions isolated from the liver of CP-administered rats were significantly attenuated by the combinatorial doses of antioxidants. EGCG + CoQ10 ameliorated the CP-induced compromised antioxidant defenses, oxidative modification of macromolecules, decreased activities of respiratory chain enzymes, altered membrane depolarization, and swelling of liver mitochondria. Furthermore, EGCG + CoQ10 treatment inhibited CP-induced apoptosis by suppressing the activation and mitochondrial accumulation of proapoptotic proteins and preventing the inhibition of antiapoptotic protein expression, cytochrome c efflux, caspase-3 activation, and DNA fragmentation. Histological findings further confirmed the protective effects of EGCG + CoQ10 against CP-induced cellular injury. Our findings revealed that the combination of EGCG and CoQ10, owing to their individual antioxidant properties, can be an effective remedy, which by maintaining redox hemostasis attenuate the mitochondrial stress-mediated molecular and cellular processes involved in CP-induced liver toxicity and cell death.
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First Measurement of Differential Charged Current Quasielasticlike ν_{μ}-Argon Scattering Cross Sections with the MicroBooNE Detector. PHYSICAL REVIEW LETTERS 2020; 125:201803. [PMID: 33258649 DOI: 10.1103/physrevlett.125.201803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/11/2020] [Accepted: 10/02/2020] [Indexed: 06/12/2023]
Abstract
We report on the first measurement of flux-integrated single differential cross sections for charged-current (CC) muon neutrino (ν_{μ}) scattering on argon with a muon and a proton in the final state, ^{40}Ar (ν_{μ},μp)X. The measurement was carried out using the Booster Neutrino Beam at Fermi National Accelerator Laboratory and the MicroBooNE liquid argon time projection chamber detector with an exposure of 4.59×10^{19} protons on target. Events are selected to enhance the contribution of CC quasielastic (CCQE) interactions. The data are reported in terms of a total cross section as well as single differential cross sections in final state muon and proton kinematics. We measure the integrated per-nucleus CCQE-like cross section (i.e., for interactions leading to a muon, one proton, and no pions above detection threshold) of (4.93±0.76_{stat}±1.29_{sys})×10^{-38} cm^{2}, in good agreement with theoretical calculations. The single differential cross sections are also in overall good agreement with theoretical predictions, except at very forward muon scattering angles that correspond to low-momentum-transfer events.
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Search for heavy neutral leptons decaying into muon-pion pairs in the MicroBooNE detector. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.101.052001] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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First Measurement of Inclusive Muon Neutrino Charged Current Differential Cross Sections on Argon at E_{ν}∼0.8 GeV with the MicroBooNE Detector. PHYSICAL REVIEW LETTERS 2019; 123:131801. [PMID: 31697542 DOI: 10.1103/physrevlett.123.131801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/06/2019] [Indexed: 06/10/2023]
Abstract
We report the first measurement of the double-differential and total muon neutrino charged current inclusive cross sections on argon at a mean neutrino energy of 0.8 GeV. Data were collected using the MicroBooNE liquid argon time projection chamber located in the Fermilab Booster neutrino beam and correspond to 1.6×10^{20} protons on target of exposure. The measured differential cross sections are presented as a function of muon momentum, using multiple Coulomb scattering as a momentum measurement technique, and the muon angle with respect to the beam direction. We compare the measured cross sections to multiple neutrino event generators and find better agreement with those containing more complete treatment of quasielastic scattering processes at low Q^{2}. The total flux integrated cross section is measured to be 0.693±0.010(stat)±0.165(syst)×10^{-38} cm^{2}.
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First measurement of
νμ
charged-current
π0
production on argon with the MicroBooNE detector. Int J Clin Exp Med 2019. [DOI: 10.1103/physrevd.99.091102] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Autozygome-guided exome sequencing in retinal dystrophy patients reveals pathogenetic mutations and novel candidate disease genes. Genome Res 2012; 23:236-47. [PMID: 23105016 PMCID: PMC3561865 DOI: 10.1101/gr.144105.112] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Retinal dystrophy (RD) is a heterogeneous group of hereditary diseases caused by loss of photoreceptor function and contributes significantly to the etiology of blindness globally but especially in the industrialized world. The extreme locus and allelic heterogeneity of these disorders poses a major diagnostic challenge and often impedes the ability to provide a molecular diagnosis that can inform counseling and gene-specific treatment strategies. In a large cohort of nearly 150 RD families, we used genomic approaches in the form of autozygome-guided mutation analysis and exome sequencing to identify the likely causative genetic lesion in the majority of cases. Additionally, our study revealed six novel candidate disease genes (C21orf2, EMC1, KIAA1549, GPR125, ACBD5, and DTHD1), two of which (ACBD5 and DTHD1) were observed in the context of syndromic forms of RD that are described for the first time.
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Abstract
Bardet-Biedl syndrome (BBS) is a model disease for ciliopathy in humans. The remarkable genetic heterogeneity that characterizes this disease is consistent with accumulating data on the interaction between the proteins encoded by the 14 BBS genes identified to date. Previous reports suggested that such interaction may also extend to instances of oligogenic inheritance in the form of triallelism which defies the long held view of BBS as an autosomal recessive disease. In order to investigate the magnitude of triallelism in BBS, we conducted a comprehensive analysis of all 14 BBS genes as well as the CCDC28B-modifier gene in a cohort of 29 BBS families, most of which are multiplex. Two in trans mutations in a BBS gene were identified in each of these families for a total of 20 mutations including 12 that are novel. In no instance did we observe two mutations in unaffected members of a given family, or observe the presence of a third allele that convincingly acted as a modifier of penetrance and supported the triallelic model of BBS. In addition to presenting a comprehensive genotype/phenotype overview of a large set of BBS mutations, including the occurrence of nonsyndromic retinitis pigmentosa in a family with a novel BBS9 mutation, our study argues in favor of straightforward autosomal recessive BBS in most cases.
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Abstract
AIM To describe the initial clinical presentation of children with 'cone dystrophy with supranormal rod response,' a distinct retinal disorder from recessive KCNV2 mutations. METHODS Retrospective case series. RESULTS Nine children (seven families) initially examined from 2 to 8 years of age were identified. Three had a similar initial presentation of abnormal head position with head shaking and nystagmus, while the other six presented with either infantile nystagmus (without abnormal head position or head shaking), suspected congenital glaucoma (with associated nystagmus), intermittent exotropia, V-pattern esotropia, comitant esotropia or difficulty with near vision only (reading). Only two children had clinically evident retinal changes (macular discoloration), and only two had a myopic cycloplegic refraction (the child with infantile nystagmus and the glaucoma suspect who actually had megalocornea). In addition to cone dystrophy, ERGs showed delayed scotopic responses with supranormal (six), high normal (two) or normal (one) scotopic b-wave responses to bright flash. Only one ERG (with a supranormal response) did not show a broad a-wave trough response to scotopic flash. For all patients, KCNV2 sequencing revealed one of three homozygous recessive mutations (one previously reported (p.E143X), two novel (p.Y53X, p.E80D)). The three children who presented with an abnormal head position, head shaking and nystagmus and the child who presented with infantile nystagmus had several years' follow-up, during which these findings resolved (two) or decreased (two). CONCLUSIONS Initial clinical presentation varied, the most common presentation being abnormal head position, head shaking and nystagmus that improved with time. ERG findings are characteristic and specific for KCNV2 mutations but do not necessarily include a scotopic b-wave flash response that is supranormal under standard ERG conditions.
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