Behavioral Neurobiology of Huntington's Disease and Parkinson's Disease

Rebecca A G De Souza, Blair R Leavitt, Rebecca A. G. De Souza, Blair R. Leavitt, De Souza, Rebecca A. G., Leavitt, Blair R.

Hoa Huu Phuc Nguyen, M. Angela Cenci

Of the neurodegenerative diseases presented in this book, Huntington's diseaseHuntington's disease (HD) stands as the archetypal autosomal dominantly inherited neurodegenerative disorder. Its occurrence through generations of affected families was noted long before the basic genetic underpinnings of hereditary diseases was understood. The early classification of HD as a distinct hereditary neurodegenerative disorder allowed the study of this disease to lead the way in the development of our understanding of the mechanisms of human genetic disorders. Following its clinical and pathologic characterization, the causative genetic mutation in HD was subsequently identified as a trinucleotide (CAG) repeat expansion in the huntingtinHuntingtin (HTT) gene, and consequently, the HTT gene and huntingtinHuntingtin protein have been studied in great detail. Despite this concentrated effort, there is still much about the function of huntingtinHuntingtin that still remains unknown. Presented in this chapter is an overview of the current knowledge on the normal function of huntingtinHuntingtin and some of the potential neurobiologic mechanisms by which the mutant HTT gene may mediate neurodegenerationNeurodegeneration in HD.