Huntington's disease is a progressive neurodegenerative disorder caused by a mutation on chromosome 4 that results in an elongated huntingtin protein. It is inherited in an autosomal dominant pattern and usually strikes in middle age, causing movement, cognitive, and behavioral issues. There is no cure, but symptoms can be managed through medications. Future treatments focus on gene therapy to silence the mutated gene or neural transplantation, though mutant huntingtin may spread to transplanted tissue.