Huntington's disease: From molecular basis to therapeutic advances.

Huntington's disease is an autosomal dominant genetic neurodegenerative disorder, which is characterized by progressive motor dysfunction, emotional disturbances, dementia, and weight loss. The disease is caused by pathological CAG-triplet repeat extension(s), encoding polyglutamines, within the gene product, huntingtin. Huntingtin is ubiquitously expressed through the body and is a protein of uncertain molecular function(s). Mutant huntingtin, containing pathologically extended polyglutamines causes the earliest and most dramatic neuropathologic changes in the neostriatum and cerebral cortex. Extended polyglutamines confer structural conformational changes to huntingtin, which gains novel properties, resulting in aberrant interactions with multiple cellular components. The diverse and variable aberrations mediated by mutant huntingtin perturb many cellular functions essential for neuronal homeostasis and underlie pleiotropic mechanisms of Huntington's disease pathogenesis. The only approved drug for Huntington's disease is a symptomatic treatment, tetrabenazine; thus, novel neuroprotective strategies, slowing, blocking and possibly reversing disease progression, are vital for developing effective therapies.