<prompt> In Huntington chorea the causative mutation in the protein huntingtin is a:Point mutationGene deletionFrameshift mutationTrinucleotide repeat expansion  <response>: Huntington disease HD Mutation in the HTT gene which codes for protein called huntingtin which is impoant to neurons. The HTT mutation involves a DNA segment known as a CAG trinucleotide repeat. Made up of a series of three DNA building blocks cytosine, adenine, and guanine that appear multiple times in a row leading to the disease. 