Huntington’s disease is a neurodegenerative disease caused by an unstable expanded CAG repeats (>35–39 repeats) in the Huntingtin gene (HTT), which results in the production of mutant protein (mHtt) with a toxic polyglutamine (polyQ) tract (Landles and Bates, 2004). The gene discussed is HTT; the disease is neurodegenerative disease.