Publications by authors named "JJ Johnston"

Plasma, milk and tissue samples were collected from 30 dairy cattle (0.4 to 8.9 years of age) with lifetime exposures to perfluoroalkyl substances (PFAS) removed from a PFAS-contaminated farm and provided PFAS-free feed and water.

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Emerging evidence implicates common genetic variation - aggregated into polygenic scores (PGS) - in the onset and phenotypic presentation of rare diseases. Here, we comprehensively map individual polygenic liability for 1102 open-source PGS in a cohort of 3059 probands enrolled in the Genomic Answers for Kids (GA4K) rare disease study, revealing widespread associations between rare disease phenotypes and PGSs for common complex diseases and traits, blood protein levels, and brain and other organ morphological measurements. Using this resource, we demonstrate increased polygenic liability in probands with an inherited candidate disease variant (VUS) compared to unaffected carrier parents.

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  • Chronic inflammation in gastrointestinal tissues leads to disorders like Crohn's disease and ulcerative colitis, causing significant symptoms and tissue damage.
  • The study analyzed blood samples from patients with various gastrointestinal conditions to explore gene expression changes, using advanced techniques like single-cell RNA-sequencing.
  • Researchers found 730 genes with altered expression patterns, indicating both shared and unique inflammatory responses among the different disorders, which may aid in diagnosis and understanding of these conditions.
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Children with type 1 diabetes (T1D) experience an increased risk of fracture, which may be related to altered bone development. We aimed to assess differences in bone, muscle and physical activity (PA), and explore if better muscle and PA measures would mitigate bone differences between children and adolescents with T1D and typically developing peers (TDP). We matched 56 children and adolescents with T1D (mean age 11.

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  • Recent studies highlight the widespread presence of rare structural variants (rSVs) in human genomes, which can significantly affect gene expression and are often linked to rare diseases without identifiable single nucleotide variants (SNVs).
  • The researchers proposed a new method to integrate trait-relevant polygenic scores (PGS) to streamline the identification of candidate disease genes impacted by rSVs, focusing on a core set of genes likely affected by these variants.
  • In their study involving patients in the Genomic Answers for Kids program, they discovered various types of rSVs in genes associated with Autism, showing that certain rSVs often occur in regions of higher genomic constraint, emphasizing the need for further functional analysis of these variants.
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Objectives: To determine precision errors and monitoring time intervals in imaged muscle properties and neuromuscular performance, and to explore growth-related factors associated with precision errors in children.

Methods: We included 35 children (mean age 10.5yrs) in the precision study cohort and 40 children (10.

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Purpose: The American College of Medical Genetics and Genomics and the Association for Molecular Pathology have outlined a schema that allows for systematic classification of variant pathogenicity. Although gnomAD is generally accepted as a reliable source of population frequency data and ClinGen has provided guidance on the utility of specific bioinformatic predictors, there is no consensus source for identifying publications relevant to a variant. Multiple tools are available to aid in the identification of relevant variant literature, including manually curated databases and literature search engines.

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Emerging evidence implicates common genetic variation - aggregated into polygenic scores (PGS) - impacting the onset and phenotypic presentation of rare diseases. In this study, we quantified individual polygenic liability for 1,151 previously published PGS in a cohort of 2,374 probands enrolled in the Genomic Answers for Kids (GA4K) rare disease study, revealing widespread associations between rare disease phenotypes and PGSs for common complex diseases and traits, blood protein levels, and brain and other organ morphological measurements. We observed increased polygenic burden in probands with variants of unknown significance (VUS) compared to unaffected carrier parents.

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Polyadenylation is an essential process for the stabilization and export of mRNAs to the cytoplasm and the polyadenylation signal hexamer (herein referred to as hexamer) plays a key role in this process. Yet, only 14 Mendelian disorders have been associated with hexamer variants. This is likely an under-ascertainment as hexamers are not well defined and not routinely examined in molecular analysis.

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Two children are presented who have a distinct syndrome of multiple buccolingual frenula, a stiff and short fifth finger with small nails, a hypothalamic hamartoma, mild to moderate neurological impairment, and mild endocrinological symptoms. No variant assessed to be pathogenic or likely pathogenic was detected in the GLI3 gene in either child. This syndrome appears to be distinct from the inherited Pallister-Hall syndrome associated with GLI3 variants, which is characterized by hypothalamic hamartoma, mesoaxial polydactyly, and other anomalies.

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Long-read HiFi genome sequencing allows for accurate detection and direct phasing of single nucleotide variants, indels, and structural variants. Recent algorithmic development enables simultaneous detection of CpG methylation for analysis of regulatory element activity directly in HiFi reads. We present a comprehensive haplotype resolved 5-base HiFi genome sequencing dataset from a rare disease cohort of 276 samples in 152 families to identify rare (~0.

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Proteus syndrome is an extremely rare overgrowth condition caused by a somatic variant of the AKT1 gene. It can involve multiple organ systems though rarely is there symptomatic cardiac involvement. Fatty infiltration of the myocardium has been described but has not been reported to cause functional or conduction abnormalities.

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Purpose: This study aimed to assess the amount and types of clinical genetic testing denied by insurance and the rate of diagnostic and candidate genetic findings identified through research in patients who faced insurance denials.

Methods: Analysis consisted of review of insurance denials in 801 patients enrolled in a pediatric genomic research repository with either no previous genetic testing or previous negative genetic testing result identified through cross-referencing with insurance prior-authorizations in patient medical records. Patients and denials were also categorized by type of insurance coverage.

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  • The study analyzed plasma and ear notch samples from 164 Holstein cows and heifers exposed to PFAS through contaminated feed and water, measuring nine specific PFAS using advanced mass spectrometry.* -
  • PFCA compounds did not accumulate in plasma or skin, whereas longer-chain PFSAs did accumulate in both, requiring at least a year of exposure to stabilize in plasma.* -
  • Lactation status significantly influenced PFSA levels in ear notch samples, while parity and lactation status had no effect on mature cow plasma PFSA concentrations, suggesting skin samples could be an alternative for biomonitoring.*
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Deficits in bone mineral and weaker bone structure in children with type 1 diabetes (T1D) may contribute to a lifelong risk of fracture. However, there is no meta-analysis comparing bone properties beyond density between children with T1D and typically developing children (TDC). This meta-analysis aimed to assess differences and related factors in bone mineral content (BMC), density, area, micro-architecture and estimated strength between children with T1D and TDC.

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The ClinGen malignant hyperthermia susceptibility (MHS) variant curation expert panel specified the American College of Medical Genetics and Genomics/Association of Molecular Pathologists (ACMG/AMP) criteria for RYR1-related MHS and a pilot analysis of 84 variants was published. We have now classified an additional 251 variants for RYR1-related MHS according to current ClinGen standards and updated the criteria where necessary. Criterion PS4 was modified such that individuals with multiple RYR1 variants classified as pathogenic (P), likely pathogenic (LP), or variant of uncertain significance (VUS) were not considered as providing evidence for pathogenicity.

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Aims: Higher prevalence of overweight and obesity in children and adolescents with type 1 diabetes (T1D) suggests alterations are required in body composition. However, differences in body composition between children with T1D and typically developing children (TDC) have not been synthesized using meta-analysis. Therefore, we conducted a systematic review and meta-analysis to compare body composition between children with T1D and TDC, and to explore the role of disease and non-disease related factors in potential body composition differences.

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  • This study focused on a holistic genetic evaluation of patients with immune-related issues, recognizing that multiple genetic factors might contribute to their health conditions rather than just a single gene explanation.
  • Researchers analyzed genetic data from 1505 individuals, uncovering 361 molecular diagnoses linked to various immune presentations, with significant updates obtained through reanalysis and new gene discoveries.
  • The findings indicate that the majority of molecular diagnoses could inform treatment options, highlighting the potential for whole exome analysis to enhance our understanding of genetic contributions to health on a large scale.
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  • The study focused on improving diagnosis and understanding of genetic disorders in children through the Genomic Answers for Kids program by analyzing genetic information from 960 families.
  • Researchers utilized various sequencing methods, including short-read and long-read genome sequencing, alongside machine learning to prioritize genetic variants and stored the data in a structured database for future access.
  • The results showed varying diagnostic success rates, with new diagnostic information gained from structural variants and long-read sequencing, highlighting ongoing challenges in identifying variants of unknown significance in nondiagnostic cases.
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