RESUMO
We used a noninvasive electrochemical quantitative assay for IgG Abs to SARS-CoV-2 S1 Ag in saliva to investigate the kinetics of Ab response in a community-based population that had received either the Pfizer or Moderna mRNA-based vaccine. Samples were received from a total of 97 individuals, including a subset of 42 individuals who collected samples twice weekly for 3 mo or longer. In all, >840 samples were collected and analyzed. In all individuals, salivary SARS-CoV-2 S1 IgG Ab levels rose sharply in the 2-wk period after their second vaccination, with peak Ab levels seen at 10-20 d after vaccination. We observed that 20%, 10%, and 2.4% of individuals providing serial samples had a 90%, 95%, and 99% drop, respectively, from peak levels during the duration of monitoring, and in two patients, Abs fell to prevaccination levels (5%). The use of noninvasive quantitative salivary Ab measurement can allow widespread, cost-effective monitoring of vaccine response.
Assuntos
Vacina de mRNA-1273 contra 2019-nCoV/imunologia , Anticorpos Antivirais/metabolismo , Vacina BNT162/imunologia , COVID-19/imunologia , Imunoglobulina G/metabolismo , SARS-CoV-2/fisiologia , Saliva/metabolismo , Adulto , Fatores Etários , Pesquisa Participativa Baseada na Comunidade , Feminino , Humanos , Masculino , VacinaçãoRESUMO
Genetic studies of autism spectrum disorder (ASD) have established that de novo duplications and deletions contribute to risk. However, ascertainment of structural variants (SVs) has been restricted by the coarse resolution of current approaches. By applying a custom pipeline for SV discovery, genotyping, and de novo assembly to genome sequencing of 235 subjects (71 affected individuals, 26 healthy siblings, and their parents), we compiled an atlas of 29,719 SV loci (5,213/genome), comprising 11 different classes. We found a high diversity of de novo mutations, the majority of which were undetectable by previous methods. In addition, we observed complex mutation clusters where combinations of de novo SVs, nucleotide substitutions, and indels occurred as a single event. We estimate a high rate of structural mutation in humans (20%) and propose that genetic risk for ASD is attributable to an elevated frequency of gene-disrupting de novo SVs, but not an elevated rate of genome rearrangement.
Assuntos
Transtorno do Espectro Autista/genética , Deleção de Genes , Duplicação Gênica , Alelos , Sequência de Aminoácidos , Sequência de Bases , Estudos de Casos e Controles , Criança , Variações do Número de Cópias de DNA , Feminino , Frequência do Gene , Rearranjo Gênico , Loci Gênicos , Genoma Humano , Técnicas de Genotipagem , Humanos , Mutação INDEL , Masculino , Análise em Microsséries , Dados de Sequência Molecular , Linhagem , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: The National Comprehensive Cancer Network recommends that women who carry gene variants that confer substantial risk for breast cancer consider risk-reduction strategies, that is, enhanced surveillance (breast magnetic resonance imaging and mammography) or prophylactic surgery. Pathogenic variants can be detected in women with a family history of breast or ovarian cancer syndromes by multigene panel testing. OBJECTIVES: To investigate whether using a seven-gene test to identify women who should consider risk-reduction strategies could cost-effectively increase life expectancy. METHODS: We estimated effectiveness and lifetime costs from a payer perspective for two strategies in two hypothetical cohorts of women (40-year-old and 50-year-old cohorts) who meet the National Comprehensive Cancer Network-defined family history criteria for multigene testing. The two strategies were the usual test strategy for variants in BRCA1 and BRCA2 and the seven-gene test strategy for variants in BRCA1, BRCA2, TP53, PTEN, CDH1, STK11, and PALB2. Women found to have a pathogenic variant were assumed to undergo either prophylactic surgery or enhanced surveillance. RESULTS: The incremental cost-effectiveness ratio for the seven-gene test strategy compared with the BRCA1/2 test strategy was $42,067 per life-year gained or $69,920 per quality-adjusted life-year gained for the 50-year-old cohort and $23,734 per life-year gained or $48,328 per quality-adjusted life-year gained for the 40-year-old cohort. In probabilistic sensitivity analysis, the seven-gene test strategy cost less than $100,000 per life-year gained in 95.7% of the trials for the 50-year-old cohort. CONCLUSIONS: Testing seven breast cancer-associated genes, followed by risk-reduction management, could cost-effectively improve life expectancy for women at risk of hereditary breast cancer.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Detecção Precoce de Câncer/economia , Perfilação da Expressão Gênica/economia , Testes Genéticos/economia , Custos de Cuidados de Saúde , Expectativa de Vida , Anos de Vida Ajustados por Qualidade de Vida , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/economia , Neoplasias da Mama/terapia , Análise Custo-Benefício , Técnicas de Apoio para a Decisão , Detecção Precoce de Câncer/métodos , Feminino , Predisposição Genética para Doença , Hereditariedade , Humanos , Imageamento por Ressonância Magnética/economia , Mamografia/economia , Mastectomia/economia , Pessoa de Meia-Idade , Modelos Econômicos , Seleção de Pacientes , Fenótipo , Valor Preditivo dos Testes , Prognóstico , Medição de Risco , Fatores de Risco , Conduta Expectante/economiaRESUMO
We developed a rules-based scoring system to classify DNA variants into five categories including pathogenic, likely pathogenic, variant of uncertain significance (VUS), likely benign, and benign. Over 16,500 pathogenicity assessments on 11,894 variants from 338 genes were analyzed for pathogenicity based on prediction tools, population frequency, co-occurrence, segregation, and functional studies collected from internal and external sources. Scores were calculated by trained scientists using a quantitative framework that assigned differential weighting to these five types of data. We performed descriptive and comparative statistics on the dataset and tested interobserver concordance among the trained scientists. Private variants defined as variants found within single families (n = 5,182), were either VUS (80.5%; n = 4,169) or likely pathogenic (19.5%; n = 1,013). The remaining variants (n = 6,712) were VUS (38.4%; n = 2,577) or likely benign/benign (34.7%; n = 2,327) or likely pathogenic/pathogenic (26.9%, n = 1,808). Exact agreement between the trained scientists on the final variant score was 98.5% [95% confidence interval (CI) (98.0, 98.9)] with an interobserver consistency of 97% [95% CI (91.5, 99.4)]. Variant scores were stable and showed increasing odds of being in agreement with new data when re-evaluated periodically. This carefully curated, standardized variant pathogenicity scoring system provides reliable pathogenicity scores for DNA variants encountered in a clinical laboratory setting.
Assuntos
Biologia Computacional/métodos , Predisposição Genética para Doença , Variação Genética , Genômica/métodos , Software , Humanos , Variações Dependentes do Observador , Reprodutibilidade dos Testes , NavegadorRESUMO
As next-generation sequencing increases access to human genetic variation, the challenge of determining clinical significance of variants becomes ever more acute. Germline variants in the BRCA1 and BRCA2 genes can confer substantial lifetime risk of breast and ovarian cancer. Assessment of variant pathogenicity is a vital part of clinical genetic testing for these genes. A database of clinical observations of BRCA variants is a critical resource in that process. This article describes BRCA Share™, a database created by a unique international alliance of academic centers and commercial testing laboratories. By integrating the content of the Universal Mutation Database generated by the French Unicancer Genetic Group with the testing results of two large commercial laboratories, Quest Diagnostics and Laboratory Corporation of America (LabCorp), BRCA Share™ has assembled one of the largest publicly accessible collections of BRCA variants currently available. Although access is available to academic researchers without charge, commercial participants in the project are required to pay a support fee and contribute their data. The fees fund the ongoing curation effort, as well as planned experiments to functionally characterize variants of uncertain significance. BRCA Share™ databases can therefore be considered as models of successful data sharing between private companies and the academic world.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Bases de Dados Factuais , Neoplasias Ovarianas/genética , Curadoria de Dados , Bases de Dados Factuais/economia , Feminino , Predisposição Genética para Doença , Humanos , MutaçãoRESUMO
PURPOSE: Recent published studies have demonstrated the incremental value of the use of cell-free DNA for noninvasive prenatal testing with 100% sensitivity for trisomies 21 and 18 and a specificity of ≥99.7% for both. Data presented by two independent groups suggesting positive results by noninvasive prenatal testing were not confirmed by cytogenetic studies. METHODS: Concordance of results among cases with noninvasive prenatal testing referred for cytogenetic prenatal and/or postnatal studies by karyotyping, fluorescence in situ hybridization, and/or oligo-single-nucleotide polymorphism microarray was evaluated for 109 consecutive specimens. RESULTS: Cytogenetic results were positive for trisomy 21 in 38 of the 41 noninvasive prenatal testing-positive cases (true-positive rate: 93%) and for trisomy 18 in 16 of the 25 noninvasive prenatal testing-positive cases (true-positive rate: 64%). The true-positive rate was only 44% (7/16 cases) for trisomy 13 and 38% (6/16 cases) for sex chromosome aneuploidy. CONCLUSION: These findings raise concerns about the limitations of noninvasive prenatal testing and the need for analysis of a larger number of false-positive cases to provide true positive predictive values for noninvasive testing and to search for potential biological or technical causes. Our data suggest the need for a careful interpretation of noninvasive prenatal testing results and cautious transmission of the same to providers and patients.
Assuntos
Análise Citogenética/métodos , Síndrome de Down/diagnóstico , Diagnóstico Pré-Natal/métodos , Trissomia/diagnóstico , Sistema Livre de Células , Cromossomos Humanos Par 18 , Feminino , Humanos , Gravidez , Sensibilidade e Especificidade , Síndrome da Trissomía do Cromossomo 18RESUMO
OBJECTIVE: We sought to report on laboratory and clinical experience following 6 months of clinical implementation of a single-nucleotide polymorphism-based noninvasive prenatal aneuploidy test in high- and low-risk women. STUDY DESIGN: All samples received from March through September 2013 and drawn ≥9 weeks' gestation were included. Samples that passed quality control were analyzed for trisomy 21, trisomy 18, trisomy 13, and monosomy X. Results were reported as high or low risk for fetal aneuploidy for each interrogated chromosome. Relationships between fetal fraction and gestational age and maternal weight were analyzed. Follow-up on outcome was sought for a subset of high-risk cases. False-negative results were reported voluntarily by providers. Positive predictive value (PPV) was calculated from cases with an available prenatal or postnatal karyotype or clinical evaluation at birth. RESULTS: Samples were received from 31,030 patients, 30,705 met study criteria, and 28,739 passed quality-control metrics and received a report detailing aneuploidy risk. Fetal fraction correlated positively with gestational age, and negatively with maternal weight. In all, 507 patients received a high-risk result for any of the 4 tested conditions (324 trisomy 21, 82 trisomy 18, 41 trisomy 13, 61 monosomy X; including 1 double aneuploidy case). Within the 17,885 cases included in follow-up analysis, 356 were high risk, and outcome information revealed 184 (51.7%) true positives, 38 (10.7%) false positives, 19 (5.3%) with ultrasound findings suggestive of aneuploidy, 36 (10.1%) spontaneous abortions without karyotype confirmation, 22 (6.2%) terminations without karyotype confirmation, and 57 (16.0%) lost to follow-up. This yielded an 82.9% PPV for all aneuploidies, and a 90.9% PPV for trisomy 21. The overall PPV for women aged ≥35 years was similar to the PPV for women aged <35 years. Two patients were reported as false negatives. CONCLUSION: The data from this large-scale report on clinical application of a commercially available noninvasive prenatal test suggest that the clinical performance of this single-nucleotide polymorphism-based noninvasive prenatal test in a mixed high- and low-risk population is consistent with performance in validation studies.
Assuntos
Transtornos Cromossômicos/diagnóstico , DNA/genética , Síndrome de Down/diagnóstico , Trissomia/diagnóstico , Síndrome de Turner/diagnóstico , Adolescente , Adulto , Aneuploidia , Peso Corporal , Transtornos Cromossômicos/genética , Cromossomos Humanos Par 13/genética , Cromossomos Humanos Par 18/genética , DNA/sangue , Síndrome de Down/genética , Feminino , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Valor Preditivo dos Testes , Gravidez , Diagnóstico Pré-Natal , Estudos Retrospectivos , Trissomia/genética , Síndrome da Trissomia do Cromossomo 13 , Síndrome da Trissomía do Cromossomo 18 , Síndrome de Turner/genética , Adulto JovemRESUMO
PURPOSE: We sought to determine the genotype frequencies for cytochrome p450 enzyme 2C19 variant alleles both in the US pan-ethnic population and various US ethnic groups and to establish the frequency of clinically actionable genotypes. METHODS: Analytical results were obtained from 1,396 consecutive samples submitted for cytochrome p450 enzyme 2C19 genotyping tests and stored in a proprietary database. This database was queried and genotypes and predicted phenotypes established. Anonymized samples were obtained from specimens submitted for cystic fibrosis genotyping that contained ethnicity information. Samples from 357, 149, and 346 individuals self-identified as white, African American, and Hispanic, respectively, were analyzed. In addition, 342 anonymized samples submitted for Ashkenazi Jewish panel testing were analyzed. RESULTS: Significant ethnic differences were observed in the frequencies of the *17 ultrarapid allele among the various groups studied. In the pan-ethnic population, 3.8% of tested patients were classified as ultrarapid metabolizers, 24% as extensive metabolizers heterozygous for a *17 ultrarapid allele, 27% as intermediate metabolizers, and 3.5% as poor metabolizers. Using stringent criteria, 7.3% of individuals would have clinically actionable genotypes. In addition, we detected two individuals with a haplotype of *2/*17 and a single individual with a haplotype of *4/*17 indicating that the *17 hypermetabolic allele can occur on a *1, *2, or *4 background.
Assuntos
Alelos , Hidrocarboneto de Aril Hidroxilases/genética , Frequência do Gene , Variação Genética , Técnicas de Laboratório Clínico , Citocromo P-450 CYP2C19 , Etnicidade/genética , Genótipo , Humanos , Fenótipo , Estados UnidosAssuntos
Ácidos Nucleicos Livres/análise , Deleção Cromossômica , Cromossomos Humanos X , Diagnóstico Pré-Natal/métodos , Síndrome de Turner/diagnóstico , Adulto , Ácidos Nucleicos Livres/sangue , Aberrações Cromossômicas , Feminino , Humanos , Gravidez , Primeiro Trimestre da Gravidez/sangue , Síndrome de Turner/genéticaRESUMO
OBJECTIVE: To determine the sensitivity and specificity of hyperglycosylated hCG (hhCG) measurements for the diagnosis of clinical pregnancies in the IVF setting and how soon post embryo transfer (ET) a pregnancy can be detected using an ultrasensitive (hhCG) assay. To determine if a single, early hhCG measurement can discriminate between biochemical and clinical pregnancies. DESIGN: A 4 center prospective blinded clinical trial was performed with patients undergoing IVF-ET. Patients had blood drawn and submitted for hhCG analysis on the day of ET and at days 4, 6, 8, and 12 thereafter. First morning urines were collected and submitted for hhCG analysis on days 0, 4, 6, 8, 10 and 12. SETTING: Fertility Centers OUTCOME MEASURES: Clinical pregnancies were defined as an ultrasound study demonstrating a gestational sac and/or heart beat at appropriate gestational ages. RESULTS: Fifty-six of 58 enrolled patients completed the study. There were 25 clinical and 6 biochemical pregnancies. For blastocyst transfers, a single serum or urine hhCG measurement identified pregnancies (both biochemical and clinical) at 6 days post ET with 100% sensitivity and specificity. There were 6 biochemical pregnancies, all following blastocyst transfers. All of these pregnancies were identified by lower values.
Assuntos
Gonadotropina Coriônica/sangue , Fertilização in vitro , Testes de Gravidez/métodos , Adulto , Transferência Embrionária , Feminino , Glicosilação , Humanos , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Sensibilidade e Especificidade , Adulto JovemRESUMO
The emergence of Omicron and Delta variants of SARS-CoV-2 has begun a number of discussions regarding breakthrough infection, waning immunity, need and timing for vaccine boosters and whether existing mRNA vaccines for the wildtype strain are adequate. Our work leverages a biosensor-based technique to evaluate the binding efficacy of SARS-CoV-2 S1 specific salivary antibodies to the Omicron and Delta variants using a cohort of mRNA vaccinated (n=109) and convalescent (n=19) subjects. We discovered a wide range of binding efficacies to the variant strains, with a mean reduction of 60.5%, 26.7%, and 14.7% in measurable signal to the Omicron strain and 13.4%, 2.4%, and âË'6.4% percent mean reduction to the Delta Variant for convalescent, Pfizer, and Moderna vaccinated groups respectively. This assay may be an important tool in determining susceptibility to infection or need for booster immunization as the pandemic evolves. Key Points: AMPERIAL assay developed to quantify salivary SARS-CoV-2 S1 IgG antibodies to Omicron and Delta variantsThere was a reduction in affinity to both Delta and Omicron VariantsThe reduction in affinity was more pronounced to Omicron than for Delta VariantsThere was a significant difference between IgG affinities in Individuals vaccinated with Pfizer versus Moderna Vaccines.
RESUMO
The emergence of the omicron and delta variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has begun a number of discussions regarding breakthrough infection, waning immunity, need and timing for vaccine boosters, and whether existing mRNA vaccines for the original SARS-CoV-2 strain are adequate. Our work leverages a biosensor-based technique to evaluate the binding efficacy of SARS-CoV-2 S1-specific salivary Abs to the omicron and delta variants using a cohort of mRNA-vaccinated (n = 109) and convalescent (n = 19) subjects. We discovered a wide range of binding efficacies to the variant strains, with a mean reduction of 60.5, 26.7, and 14.7% in measurable signal to the omicron strain and 13.4, 2.4, and -6.4% mean reduction to the delta variant for convalescent, Pfizer-, and Moderna-vaccinated groups, respectively. This assay may be an important tool in determining susceptibility to infection or need for booster immunization as the pandemic evolves.
Assuntos
COVID-19 , Vacinas Virais , Anticorpos Antivirais , Afinidade de Anticorpos , COVID-19/prevenção & controle , Humanos , Imunoglobulina G , RNA Mensageiro , SARS-CoV-2RESUMO
PURPOSE: : Recently, a major CLIA-certified commercial laboratory began offering an extended cystic fibrosis (CF) carrier screening panel containing 103 variants including p.L997F. Our laboratory has already received two invasive prenatal diagnostic samples where one parent carries a classic CF mutation and the other carries p.L997F. One fetus inherited both variants. METHODS: : We queried our databases containing >2500 CF sequencing analyses to find all individuals with the p.L997F variant. For all compound heterozygous patients, clinical information was obtained by a genetic counselor telephoning the medical provider. RESULTS: : There were four compound heterozygous patients carrying the p.L997F variant and a second pathogenic CF allele. Three patients were discovered by newborn screening and were asymptomatic at ages 28, 40, and 60 months, respectively. The fourth individual is currently aged 10 years and has the diagnosis of atypical CF with recurrent pancreatitis, sinusitis with nasal polyps, and mild lung disease. His length and weight are in the 90th and 75th centile, respectively. The fifth patient was a compound heterozygote for p.F508del and a complex allele containing p.L997F and a deletion of exons 2-9. This patient has the diagnosis of classical CF. CONCLUSION: : The p.L997F variant is not a classical CF mutation, and its inclusion in population-based carrier screening panels is a disservice to couples who may make poorly informed reproductive decisions based on incorrect assumptions.
Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/genética , Testes Genéticos/ética , Mutação , Triagem Neonatal/métodos , Vigilância da População , Alelos , Criança , Pré-Escolar , Fibrose Cística/diagnóstico , Fibrose Cística/genética , Análise Mutacional de DNA , Éxons , Estudos de Associação Genética , Aconselhamento Genético , Testes Genéticos/métodos , Testes Genéticos/normas , Genótipo , Heterozigoto , Humanos , Recém-Nascido , FenótipoRESUMO
PURPOSE: Fragile X syndrome is caused by expansion and methylation of a CGG tract in the 5' untranslated region of the FMR1 gene. The estimated frequency of expanded alleles (≥55 repeats) in the United States is 1:257-1:382, but these estimates were not calculated from unbiased populations. We sought to determine the frequency of fragile X syndrome premutation (55-200 repeats) and full mutation (>200 repeats) alleles in nonselected, unbiased populations undergoing routine carrier screening for other diseases. METHODS: A previously validated laboratory-developed test using triplet-primed polymerase chain reaction was used to detect premutation and full mutation alleles in an unselected series of 11,759 consecutive cystic fibrosis carrier screening samples and 2011 samples submitted for screening for genetic diseases prevalent among the Ashkenazi Jewish population. RESULTS: Premutations were identified in 48 cystic fibrosis screening samples (1:245) and 15 samples (1:134) from the Ashkenazi Jewish population. Adjusted for the ethnic mix of the US population and self-reported ethnicity in our screening population, the estimated female premutation carrier frequency in the United States was 1:178. The calculated frequency of full mutation alleles was 1:3335 overall, and the calculated premutation frequency in males was 1:400. Based on frequency of larger, ≥70 repeat alleles, and reported penetrance, the calculated fragile X-associated tremor and ataxia syndrome, and fragile X-associated primary ovarian insufficiency frequencies is 1:4848 and 1:3560, respectively. CONCLUSION: Our calculated fragile X syndrome carrier rate is higher than previous estimates for the US population and warrants further consideration of population-based carrier screening.
Assuntos
Ataxia/genética , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/epidemiologia , Síndrome do Cromossomo X Frágil/genética , Insuficiência Ovariana Primária/genética , Tremor/genética , Ataxia/epidemiologia , Ataxia/etiologia , Portador Sadio , Feminino , Síndrome do Cromossomo X Frágil/complicações , Frequência do Gene , Testes Genéticos , Heterozigoto , Humanos , Masculino , Mutação , Prevalência , Tremor/epidemiologia , Tremor/etiologia , Estados Unidos/etnologiaRESUMO
PURPOSE: This study reviews data from our cystic fibrosis testing program to evaluate the performance of population-based carrier screening and compare observed detection rates with predicted results of the American College of Medical Genetics/American College of Obstetricians and Gynecologists recommended panel of 23 mutations. METHODS: We queried our proprietary databases containing approximately 3 million cystic fibrosis screening tests, 1300 prenatal diagnostic tests, and 2400 cystic fibrosis sequencing analyses. RESULTS: We observed an overall cystic fibrosis carrier frequency of 1:37.6 individuals in the pan-ethnic tested population. This represents a detection rate of 77%, given an estimated US pan-ethnic carrier frequency of 1:29. For patients self-identified as white or Ashkenazi Jewish, a carrier frequency of 1:29 and 1:27 were observed, respectively. A combined frequency of 1:28, representing close to 90% of carriers, was identified in these two highest risk populations. In total, 119 affected fetuses were identified by prenatal diagnoses, a ratio of 1 affected fetus per 25,000 carrier screens. Of 62 newborns with positive immunoreactive trypsinogen and positive sweat tests, almost all of whom had been tested using the American College of Medical Genetics/American College of Obstetricians and Gynecologists panel, only two individuals would have been identified using an expanded mutation panel. CONCLUSION: The American College of Medical Genetics/American College of Obstetricians and Gynecologists panel of 23 mutations is performing as predicted in detecting cystic fibrosis carriers in the United States among all ethnic groups. No recurrent mutations have been detected in sufficient numbers to justify including any additional mutations to the existing panel. An expanded American College of Medical Genetics/American College of Obstetricians and Gynecologists panel would have a minimal impact on the prevention of births of children affected with cystic fibrosis.
Assuntos
Fibrose Cística/diagnóstico , Fibrose Cística/genética , Triagem de Portadores Genéticos/métodos , Testes Genéticos/métodos , Criança , Fibrose Cística/epidemiologia , Fibrose Cística/etnologia , Análise Mutacional de DNA , Frequência do Gene , Heterozigoto , Humanos , Recém-Nascido , Mutação , Prevalência , Grupos Raciais/genética , Estados Unidos/epidemiologia , Estados Unidos/etnologiaRESUMO
Amperial™ is a novel assay platform that uses immobilized antigen in a conducting polymer gel followed by detection via electrochemical measurement of oxidation-reduction reaction between H2O2/Tetrametylbenzidine and peroxidase enzyme in a completed assay complex. A highly specific and sensitive assay was developed to quantify levels of IgG antibodies to SARS-CoV-2 in saliva. After establishing linearity and limit of detection we established a reference range of 5 standard deviations above the mean. There were no false positives in 667 consecutive saliva samples obtained prior to 2019. Saliva was obtained from 34 patients who had recovered from documented COVID-19 or had documented positive serologies. All of the patients with symptoms severe enough to seek medical attention had positive antibody tests and 88% overall had positive results. We obtained blinded paired saliva and plasma samples from 14 individuals. The plasma was analyzed using an EUA-FDA cleared ELISA kit and the saliva was analyzed by our Amperial™ assay. All 5 samples with negative plasma titers were negative in saliva testing. Eight of the 9 positive plasma samples were positive in saliva and 1 had borderline results. A CLIA validation was performed as a laboratory developed test in a high complexity laboratory. A quantitative non-invasive saliva based SARS-CoV-2 antibody test was developed and validated with sufficient specificity to be useful for population-based monitoring and monitoring of individuals following vaccination.
Assuntos
Anticorpos Antivirais/imunologia , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Imunoglobulina G/imunologia , SARS-CoV-2/imunologia , Saliva/imunologia , Anticorpos Antivirais/análise , COVID-19/imunologia , COVID-19/virologia , Técnicas Eletroquímicas/métodos , Humanos , Imunoglobulina G/análise , Limite de Detecção , SARS-CoV-2/isolamento & purificação , Saliva/virologiaRESUMO
PURPOSE: Fragile X syndrome is caused by expansion and subsequent methylation of a CGG trinucleotide repeat in the FMR1 5'-untranslated region. Southern blot analysis is typically required to determine expansion size for triplet repeat lengths >200. We describe a triplet-primed polymerase chain reaction-based method using automated capillary electrophoresis detection for qualitative assessment of expanded CGG repeats. METHODS: The assay uses triplet-primed polymerase chain reaction in combination with GC-melting reagents and substitution of 7-deaza-2-deoxyGTP for dGTP. Amplicons are resolved by capillary electrophoresis. RESULTS: A distinctive pattern of tapering or "stutter" polymerase chain reaction amplification was evident on capillary electrophoresis in male and female patients harboring all expanded allele lengths examined (up to 2000 CGG repeats) and could be used to differentiate normal, intermediate, premutation, and full mutation alleles. Full mutation alleles exhibited an additional late-migrating amplicon on capillary electrophoresis. Mixing experiments demonstrated sensitivity as low as 1% for detection of the full mutation allele. In a 1275-sample concordance study against our existing polymerase chain reaction platform (with Southern blot analysis for repeat lengths ≥55), the triplet-primed polymerase chain reaction method exhibited 100% concordance for normal, intermediate, expanded, and full mutation alleles. This method also detected the full mutation alleles in DNA isolated from blood spots. CONCLUSION: This assay provides an accurate assessment of FMR1 repeat status and holds promise for use in carrier and newborn screening. The method distinguishes normal homozygous females from full mutation carrying females. Although the method is not useful for accurate sizing, it supplements the classic polymerase chain reaction method and results in significant reduction in the number of Southern blot analyses required to be performed in the laboratory to accurately assess the FMR1 genotype in all individuals.
Assuntos
Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/diagnóstico , Síndrome do Cromossomo X Frágil/genética , Mosaicismo , Mutação , Triagem Neonatal , Repetições de Trinucleotídeos , Regiões 5' não Traduzidas/genética , Southern Blotting , DNA/genética , Eletroforese Capilar , Feminino , Testes Genéticos , Heterozigoto , Humanos , Recém-Nascido , Masculino , Reação em Cadeia da Polimerase , Avaliação da Tecnologia BiomédicaRESUMO
The purpose of this study was to determine whether combining different testing modalities namely beta-hexosaminidase A (HEXA) enzyme analysis, HEXA DNA common mutation assay, and HEXA gene sequencing could improve the sensitivity for carrier detection in non-Ashkenazi (AJ) individuals. We performed a HEXA gene sequencing assay, a HEXA DNA common mutation assay, and a HEXA enzyme assay on 34 self-reported Tay-Sachs disease (TSD) carriers, six late-onset patients with TSD, and one pseudodeficiency allele carrier. Sensitivity of TSD carrier detection was 91% for gene sequencing compared with 91% for the enzyme assay and 52% for the DNA mutation assay. Gene sequencing combined with enzyme testing had the highest sensitivity (100%) for carrier detection. Gene sequencing detected four novel mutations, three of which are predicted to be disease causing [118.delT, 965A-->T (D322V), and 775A-->G (T259A)]. Gene sequencing is useful in identifying rare mutations in patients with TSD and their families, in evaluating spouses of known carriers for TSD who have indeterminate enzyme analysis and negative for common mutation analysis, and in resolving ambiguous enzyme testing results.
Assuntos
Ensaios Enzimáticos Clínicos , Análise Mutacional de DNA , Testes Genéticos , Mutação , Doença de Tay-Sachs/diagnóstico , Cadeia alfa da beta-Hexosaminidase/genética , Adulto , Idade de Início , Feminino , Predisposição Genética para Doença , Heterozigoto , Humanos , Masculino , Fenótipo , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Doença de Tay-Sachs/enzimologia , Doença de Tay-Sachs/etnologia , Doença de Tay-Sachs/genética , Cadeia alfa da beta-Hexosaminidase/sangueRESUMO
Amperial™ is a novel assay platform that uses immobilized antigen in a conductive polymer gel followed by an electrochemical detection. A highly specific and sensitive assay was developed to quantify levels of IgG antibodies to SARS-CoV-2 in saliva. After establishing linearity and limit of detection we established a reference range of 5 standard deviations above the mean. There were no false positives in 667 consecutive saliva samples obtained prior to 2019. Saliva was obtained from 34 patients who had recovered from documented COVID-19 or had documented positive serologies. All of the patients with symptoms severe enough to seek medical attention had positive antibody tests and 88% overall had positive results. We obtained blinded paired saliva and plasma samples from 14 individuals. The plasma was analyzed using an EUA-FDA cleared ELISA kit and the saliva was analyzed by our Amperial™ assay. All 5 samples with negative plasma titers were negative in saliva testing. Eight of the 9 positive plasma samples were positive in saliva and 1 had borderline results. A CLIA validation was performed as a laboratory developed test in a high complexity laboratory. A quantitative non-invasive saliva based SARSCoV-2 antibody test was developed and validated with sufficient specificity to be useful for population-based monitoring and monitoring of individuals following vaccination.