Final answer:
Huntington's disease (HD) is ultimately responsible for the toxicity in HD. It is an inherited degenerative disorder caused by a mutation in the huntington gene. The mutated protein leads to the death and degeneration of neurons in the brain.
Step-by-step explanation:
Huntington's disease (HD) is responsible for the toxicity in HD. HD is an inherited degenerative disorder that results in the death of certain neurons in the brain. This progressive disorder is caused by a mutation in the gene that encodes the huntington protein. The mutated protein leads to the production of a longer than normal sequence of glutamine residues, which ultimately causes the death and degeneration of neurons.