Publications by authors named "Devon L Johnstone"

Background And Objectives: To expand the clinical knowledge of 1-related glycosylphosphatidylinositol (GPI) deficiency.

Methods: An international case series of 7 patients with biallelic variants were identified. Clinical, biochemical, and neuroimaging data were collected for comparison.

View Article and Find Full Text PDF

We investigated seven children from six families to expand the phenotypic spectrum associated with an early infantile epileptic encephalopathy caused by biallelic pathogenic variants in the phosphatidylinositol glycan anchor biosynthesis class Q (PIGQ) gene. The affected children were all identified by clinical or research exome sequencing. Clinical data, including EEGs and MRIs, was comprehensively reviewed and flow cytometry and transfection experiments were performed to investigate PIGQ function.

View Article and Find Full Text PDF
Article Synopsis
  • Biallelic pathogenic variants in the PLPBP gene cause a unique form of vitamin B6-dependent epilepsy, which can lead to severe consequences such as status epilepticus and death during infancy if untreated.
  • Researchers identified 12 new patients and six novel variants linked to this condition, with the most severe cases associated with variants that cause loss of function or destabilize the PLPBP protein.
  • A zebrafish model created using CRISPR/Cas9 mimics the disease's symptoms and shows that treatment with pyridoxine can alleviate seizures and prolong life, while also revealing important metabolic disruptions linked to the disease.
View Article and Find Full Text PDF

Zebrafish (Danio rerio) possess orthologues for 84% of the genes known to be associated with human diseases. In addition, these animals have a short generation time, are easy to handle, display a high reproductive rate, low cost, and are easily amenable to genetic manipulations by microinjection of DNA in embryos. Recent advances in gene editing tools are enabling precise introduction of mutations and transgenes in zebrafish.

View Article and Find Full Text PDF

There are over 150 known human proteins which are tethered to the cell surface via glycosylphosphatidylinositol (GPI) anchors. These proteins play a variety of important roles in development, and particularly in neurogenesis. Not surprisingly, mutations in the GPI anchor biosynthesis and remodeling pathway cause a number of developmental disorders.

View Article and Find Full Text PDF

We describe temporal changes in the genetic composition of a small anadromous Atlantic salmon (Salmo salar) population from South Newfoundland, an area where salmon populations are considered threatened (COSEWIC 2010). We examined the genetic variability (13 microsatellite loci) in 869 out-migrating smolt and post-spawning kelt samples, collected from 1985 to 2011 for a total of 22 annual collections and a 30 year span of assigned cohorts. We estimated the annual effective number of breeders (Nb) and the generational effective population size (Ne) through genetic methods and demographically using the adult sex ratio.

View Article and Find Full Text PDF