Evidence based molecular pathways, available drug targets, pre- clinical animal models and future disease modifying treatments of huntington's disease

Abstract

Huntington's disease is an autosomal dominant neurodegenerative disorder of variable progression. Its major features are motor dysfunction, cognitive decline, and psychiatric disturbances. The onset of HD in a patient occurs because of a polyglutamine-expanding mutation within the HTT gene, which leads to the formation of mutant huntingtin protein that aggregates and disrupts neuronal function. Epidemiologically, HD afflicts about 5-10 people per 100,000 throughout the world. However, among populations of European descent, its prevalence is increased. Even after much study into the disorder, myths prevail relating to onset and inheritance of this disorder; including myths such as non-genetic transmission, along with myths such as variation in symptoms, the myths feed on stigma, contributing to a delay in diagnosis and management. Neurodegenerative level in HD affects the basal ganglia especially the striatum leading to impaired motor coordination, chorea, and cognitive deficits. Pathophysiology encompasses excitotoxicity, mitochondrial dysfunction, oxidative stress, and impaired protein clearance mechanisms that end in neuronal loss. The future research areas in the management of HD include gene silencing techniques, stem cell therapy, and even advanced neuroprotective agents acting through a disease-modifying mechanism. The hope of CRISPR-Cas9 gene editing is correction at the source level, and ASOs target reduction in the expression of the mutant huntingtin protein. The introduction of personalized medicine for discovery based on biomarkers could further buttress early diagnosis and effectiveness of treatment. The most revolutionary approach towards the treatment of HD can be a multi-disciplinary approach encompassing conventional therapies and novel genetic techniques.

Keywords: Brain-derived neurotropic factor; Excitoxicity; Huntington’s disease; Mutant Huntingtin; Oxidative stress; Synthetic drugs.