Emergence of Hereditary Hyperplastic Gingivitis in Newfoundland and Labrador, Canada: An Exploration into the Molecular Aetiology at Both the Gene and Genome Levels

The study explored the molecular aetiology of hereditary hyperplastic gingivitis (HHG) in silver foxes in Newfoundland and Labrador, Canada, following the introduction of a Finnish fox line. HHG, an autosomal recessive condition with male sex-biased penetrance, was investigated for its genetic basis by examining genes related to a similar human condition, hereditary gingival fibromatosis (HGF). Although no mutations were found in candidate genes like the son of sevenless homolog 1, global gene expression analysis identified SOS2 and RASA1 as potential candidates, implicating the mitogen-activated protein kinase (MAPK) signalling pathway. The study suggested that errors in this pathway, possibly influenced by androgens, could underlie HHG, with the steroid-5-alpha-reductase, alpha polypeptide 2 gene being up-regulated in affected foxes. This research provided insights into the genetic and molecular mechanisms of gingival overgrowth, with implications for understanding similar conditions in humans and canines.