The heat-shock proteins (HSPs) belong to a larger group of polypeptides, the stress proteins, that are induced in various combinations in response to environmental challenges and developmental transitions. Heat-shock 27-kD protein1also knows as HSPB. Synthesis of the small (27-kD) HSP has been shown to be correlated with the acquisition of thermotolerance. HSP27 gene is mapped to 7q11.23. Mutant small heat-shock protein 27 causes axonal Charcot-Marie-Tooth disease and distal hereditary motor neuropathy. Heat shock protein 27 prevents cellular polyglutamine toxicity and suppresses the increase of reactive oxygen species caused by huntingtin.