Publications by authors named "Taryn Athey"

CASK (MIM#300172), encoding a calcium/calmodulin-dependent serine protein kinase, is crucial for synaptic transmission and gene regulation during neural development. Pathogenic variants of CASK are known to cause several neurodevelopmental disorders, including X-linked intellectual disability and microcephaly with pontine and cerebellar hypoplasia (MICPCH). This study introduces a novel, de novo synonymous CASK variant (NM_001367721.

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Here, we introduce , an R package to determine the distribution of very low frequency variants (VLFs) in nucleotide and amino acid sequences for the analysis of errors in DNA sequence records. The package allows users to assess VLFs in aligned and trimmed protein-coding sequences by automatically calculating the frequency of nucleotides or amino acids in each sequence position and outputting those that occur under a user-specified frequency (default of = 0.001).

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Spondyloepimetaphyseal dysplasia with joint laxity, leptodactylic type (SEMDJL2), is a rare bone dysplasia that results from hotspot (amino acids148/149) mutations in KIF22. Clinically, affected individuals present with generalized joint laxity, limb malalignment, midface hypoplasia, gracile digits, postnatal short stature, and occasionally, tracheolaryngomalacia; additionally, radiological features include severe epi-metaphyseal abnormalities and slender metacarpals. This report evaluates the progression of SEMDJL2 throughout the life of the oldest individual reported in the literature-a 66-year-old man with a pathogenic KIF22 variant (c.

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Clinical exome sequencing (ES) is the most comprehensive genomic test to identify underlying genetic diseases in Canada. We performed this retrospective cohort study to investigate the diagnostic yield of clinical ES in adulthood. Inclusion criteria were: (1) Adult patients ≥18 years old; (2) Patients underwent clinical ES between January 1 and December 31, 2021; (3) Patients were seen in the Department of Medical Genetics.

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Background: Mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects are a group of inherited metabolic diseases. We performed a retrospective cohort study to report on the phenotypic and genotypic spectrum of mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects as well as their treatment outcomes.

Methods: All patients with mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects were included.

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Introduction: Childhood epilepsy is one of the most common neurological problems. The transferrin isoelectric focusing (TIEF) test is a screening test for congenital disorders of glycosylation (CDG). We identified abnormal TIEF test in children with epilepsy in our epilepsy genetics clinic.

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Background: The number of invasive group A (iGAS) infections due to hitherto extremely rare type strains has increased in several Canadian provinces since late 2015. We hypothesized that the cases recorded in the different provinces are linked and caused by strains of an clone that recently emerged and expanded explosively.

Methods: We analyzed both active and passive surveillance data for iGAS infections and used whole-genome sequencing to investigate the phylogenetic relationships of the strains responsible for these invasive infections country-wide.

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Adequacy of the current clinical definition of institutional influenza outbreaks is unclear. We performed a retrospective genome sequencing and epidemiologic analysis of institutional influenza outbreaks that occurred during the 2014-15 influenza season in Toronto, Canada. We sequenced the 2 earliest submitted samples positive for influenza A(H3N2) from each of 38 reported institutional outbreaks in long-term care facilities.

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Article Synopsis
  • The study focused on understanding how pili, which help group B Streptococcus (GBS) infect hosts, are structured and differ across various strains in Toronto, Canada.
  • Researchers analyzed 1332 GBS isolates using PCR and whole genome sequencing, discovering a new variant of a key pilin protein, named BP-1b, which showed only 63% similarity to the standard version of the protein.
  • The findings highlighted that this new variant appears frequently in specific GBS serotypes but is undetectable with common testing methods, suggesting that incorporating new PCR primers could improve the accuracy of identifying strains.
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The capsular polysaccharide (CPS) is the major virulence factor of the emerging zoonotic pathogen Streptococcus suis. CPS differences are also the basis for serological differentiation of the species into 29 serotypes. Serotypes 2 and 1/2, which possess identical gene content in their cps loci, express CPSs that differ only by substitution of galactose (Gal) by N-acetylgalactosamine (GalNAc) in the CPS side chain.

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Article Synopsis
  • Invasive group A Streptococcus (iGAS) disease is on the rise globally, particularly due to the emergence of a new variant called clade 3, which has unclear clinical characteristics.
  • A study conducted in Toronto over 14 years analyzed the genetic data of iGAS isolates, revealing a significant increase in clade 3 cases after its emergence, with overall disease incidence rising from 0.14 to 0.22 per 100,000 people.
  • Clade 3 strains are associated with more cases of arthritis but fewer instances of necrotizing fasciitis, and they predominantly affect younger and middle-aged individuals.
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  • Molecular typing through whole genome sequencing (WGS) was used to identify genetic relationships and predict antibiotic resistance in 240 invasive pneumococcal isolates from older adults in Ontario between 2009 and 2013.
  • The study found that 98.3% of isolates had their sequence type accurately determined, and WGS showed high sensitivity (95%) and specificity (100%) for predicting antibiotic resistance compared to standard testing.
  • Notably, the emerging non-vaccine serotype 22F was divided into two clades with distinct genetic features, and the findings suggest the need for enhanced molecular surveillance of pneumococcal strains in light of evolving antibiotic resistance.
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Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by . In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65.

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  • Shiga toxin-producing E. coli strains, particularly O157:H7, are linked to outbreaks and infections globally.
  • This study focuses on the high-quality draft genome sequences of 19 O157:H7 strains isolated in Argentina.
  • The findings contribute to a better understanding of these strains and their incidence in human health.
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We report several cases of recombination events leading to capsular switching among sequence type (ST) 1 group B Streptococcus strains. These strains otherwise shared a common genome backbone with serotype V ST1 strains. However, the genomes of ST1 serotype V strains and those of serotypes VI, VII, and VIII strains differed substantially.

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Article Synopsis
  • * A specific GBS strain, NGBS375, has a unique genetic makeup, combining elements from different strains, which affects its virulence during infection.
  • * Although strain NGBS375 causes less severe infections compared to a more virulent strain, it has a similar ability to provoke an immune response, suggesting that its lower virulence is likely due to its limited growth and spread in the bloodstream.
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  • Researchers have developed a new pipeline that allows for the identification of all 29 serotypes of Streptococcus suis directly from whole-genome sequencing (WGS) data.
  • This automated system uses a custom database and differential alignment techniques, successfully differentiating between previously indistinguishable serotypes through specific genetic mutations.
  • The pipeline has shown high accuracy in identifying serotypes, with a 99% match to traditional methods and a 92% match using additional genomic data, thereby resolving a long-standing challenge in S. suis classification.
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Many bacterial species coexist in the same niche as heterogeneous clones with different phenotypes; however, understanding of infectious diseases by polyphenotypic bacteria is still limited. In the present study, encapsulation in isolates of the porcine pathogen Streptococcus suis from persistent endocarditis lesions was examined. Coexistence of both encapsulated and unencapsulated S.

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Article Synopsis
  • The introduction of pneumococcal conjugate vaccines has led to the rise of non-vaccine serotypes that cause invasive pneumococcal disease globally, notably in Canada.
  • In Ontario, between 2009 and 2013, an increase in non-PCV-13 serotypes, particularly 22F, 15A, and 8, was documented, with all showing significant statistical relevance.
  • Whole genome sequencing revealed that serotype 15A isolates are multidrug-resistant and identified recombination events in serotypes 22F, 15A, and 8, highlighting the importance of genomic studies in understanding bacterial evolution and antibiotic resistance.
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  • Strains of serotype 2 Streptococcus suis cause infections in both pigs and humans, and this study explored genetic diversity within the common ST25 lineage using whole-genome sequencing.
  • The analysis of 51 strains from Canada, the U.S., and Thailand revealed significant genomic rearrangements and indicated that lateral gene transfer and recombination contribute to the genetic diversity of ST25.
  • The research identified two distinct clades corresponding to Thai and North American strains with unique antimicrobial resistance patterns and highlighted the limitations of multilocus sequence typing (MLST) for understanding S. suis evolution.
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An outbreak of type emm59 invasive group A Streptococcus (iGAS) disease was declared in 2008 in Thunder Bay District, Northwestern Ontario, 2 years after a countrywide emm59 epidemic was recognized in Canada. Despite a declining number of emm59 infections since 2010, numerous cases of iGAS disease continue to be reported in the area. We collected clinical information on all iGAS cases recorded in Thunder Bay District from 2008 to 2013.

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Streptococcus suis is a major swine pathogen and a zoonotic agent. Serotype 2 strains are the most frequently associated with disease. However, not all serotype 2 lineages are considered virulent.

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Serotype IV group B Streptococcus (GBS) is emerging in Canada and the United States with rates as high as 5% of the total burden of adult invasive GBS disease. To understand this emergence, we studied the population structure and assessed the antimicrobial susceptibility of serotype IV isolates causing adult invasive infection in Manitoba and Saskatchewan, Canada, between 2010 and 2014. Whole-genome sequencing was used to determine multilocus sequence typing information and identify genes encoding antimicrobial resistance in 85 invasive serotype IV GBS strains.

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Typing of group A Streptococcus (GAS) is crucial for infection control and epidemiology. While whole-genome sequencing (WGS) is revolutionizing the way that bacterial organisms are typed, it is necessary to provide backward compatibility with currently used typing schemas to facilitate comparisons and understanding of epidemiological trends. Here, we sequenced the genomes of 191 GAS isolates representing 42 different emm types and used bioinformatics tools to derive commonly used GAS typing information directly from the short-read WGS data.

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